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تنظیمات زمان در سرور VMware ESXi
تنظیمات زمان در سرور VMware ESXi
Time synchronization between virtual machine and ESXi server is very important. It would be really painful if you had to manually configure and sync the time between the host and virtual machines. But VMware ESXi have built in time management to make your life easier. Today I will show you how to configure NTP Server in ESXi host and sync time between the VMs and host machines.
Time Synchronization Between Virtual Machine and ESXi Server
Log in to VMware host via vSphere client. Click Inventory and select the particular host.You will now see bunch of tabs on right window. Click the configuration tab as you can see the picture below shows just that. 
Then click properties on top right corner. You will see the following dialog box after clicking it.
Now, click the Options button.
In the General tab, select Startup Policy as Start automatically if any ports are open, and stop when all ports are closed. Click Restart and click OK. Now select NTP Settings on the left pane. Here you can add the NTP server. Click add button and give the IP address or domain name of the NTP server. Then click OK.
Select the check box, Restart NTP service to apply changes and click OK. Now, click the check box, NTP Client Enabled.
Now your host gets IP address from NTP server. After getting IP from NTP server you now want to sync time between host and VMs. As we are already in vSphere client. Right click on any of the virtual machine and click edit settings. This will open up the properties of virtual machine.
Here, select the Options Tab. Click on VMware Tools on the left pane. On the right pane select the check box, Synchronize guest time with host. Now your virtual machine gets the time from your host machine.
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تفاوتهای میان vSphere ، ESXi و vCenter
تفاوتهای میان vSphere ، ESXi و vCenter
here is a lot of buzz of VMware virtualization solution these days. No doubt that VMware is the number one virtualization solution provider in the industry. People who are new to VMware’s virtualization platform often get confused while learning VMware vSphere and its components. So today I will be explaining all about vSphere and its components. Folks face difficulty to know about major components of vSphere. It’s important to know the difference between vSphere, ESXi and vCenter. To get in-depth knowledge and experience in vSphere you can install vSphere inside VMware Workstation with little cost.
Difference between vSphere, ESXi and vCenter
VMware Inc. is a software company that develops many suites of software products specially for providing various virtualization solutions. There are many cloud products, datacenter products, desktop products and so on.
vSphere is a software suite that comes under data center product. vSphere is like Microsoft Office suite which has many softwares like MS Office, MS Excel, MS Access and so on. Like Microsoft Office, vSphere is also a software suite that has many software components like vCenter, ESXi, vSphere client and so on. So, the combination of all these software components is vSphere. vSphere is not a particular software that you can install and use, “it is just a package name which has other sub components”.
ESXi, vSphere client and vCenter are components of vSphere. ESXi server is the most important part of vSphere. ESXi is the virtualization server. It is type 1 hypervisor. All the virtual machines or Guest OS are installed on ESXi server. To install, manage and access those virtual servers which sit above of ESXi server, you will need other part of vSphere suit called vSphere client or vCenter. Now, vSphere client allows administrators to connect to ESXi servers and access or manage virtual machines. vSphere client is installed on the client machine (e.g. Administrator’s laptop). The vSphere client is used from client machine to connect to ESXi server and do management tasks. So now what is vCenter? Why we need it? Try cloning existing virtual machine using just a vSphere client without vCenter server.
vCenter server is similar to vSphere client but it’s a server with more power. vCenter server is installed on Windows Server or Linux Server. VMware vCenter server is a centralized management application that lets you manage virtual machines and ESXi hosts centrally. vSphere client is used to access vCenter Server and ultimately manage ESXi servers. vCenter server is compulsory for enterprises to have enterprise features like vMotion, VMware High Availability, VMware Update Manager and VMware Distributed Resource Scheduler (DRS). For example, you can easily clone existing virtual machine in vCenter server. So vCenter is another important part of vSphere package. You have to buy vCenter license separately.
The diagram above shows vSphere suite in a more descriptive way. vSphere is a product suite, ESXi is a hypervisor installed on a physical machine. vSphere Client is installed on laptop or desktop PC and is used to access ESXi Server to install and manage virtual machines on ESXi server. vCenter server is installed as virtual machine on top of ESXi server. vCenter server can also be installed on different standalone physical server, but why not virtualize it too right? vCenter server is a vSphere component which is mostly used in large environment where there are many ESXi servers and dozens of virtual machines. The vCenter server is also accessed by vSphere client for management purpose. So, vSphere client is used to access ESXi server directly in small environment. In larger environment, vSphere client is used again to access vCenter server which ultimately manages ESXi server.
You can install vSphere in your PC to get more knowledge of this amazing technology. For more information about VMware you can visitVMware’s Official website.
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گرفتن Clone از ماشین های مجازی در VMware vCenter
گرفتن Clone از ماشین های مجازی در VMware vCenter
There are a couple of ways to clone existing virtual machine in VMware environment. You can clone virtual machine with VMware vCenter or even clone with VMware vSphere client. vCenter server has a lot of features and functionality that just works great. Here, I will show how to clone virtual machine in VMware vCenter server. Cloning functionality is very handy when deploying many virtual machines in short period. Cloning virtual machines in vCenter server is easy and has few steps.
Clone virtual machine in VMware vCenter
At first, log in to vCenter server.
Then expand the host from where you want to clone the virtual machine. Select and right-click the VM and click clone.
Type the name of new virtual machine. Then, select the inventory folder and click next button.
Now select the host where you want to store the cloned virtual machine. Click next button.
Now, select the data store to store hard disk file of the virtual machine. Click next button.
Here, you can customize the new cloned virtual machine. I will select to power on the virtual machine after creation and click next button.
Now click finish to complete the step.
After couple of seconds your cloned virtual machine will be ready for use.
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نصب SQL Server 2012 در ویندوز سرور 2012 R2
نصب SQL Server 2012 در ویندوز سرور 2012 R2
Install SQL Server 2012 in Windows Server 2012 R2
Don’t forget to checkout minimum hardware and software requirements before you install SQL Server 2012. Insert the SQL Server 2012 installation DVD. Before you start to install the SQL server, install the NetFx3 feature, otherwise you will get error while the installation is in progress. To install the NEtFx3, type the following command in command prompt as shown in the snapshot below. Make sure you have inserted the installation media.
c:\> dism /online /enable-feature /featurename:netfx3 /all /source:d:\sources\sxs
To start the SQL server installation, click the first option after selecting installation tab from the installation center as shown below. Since this is going to be new SQL server installation select the first option.
The installation will then check all the pre-requisites that are required to install the SQL server. If everything is fine, you will see green checks as shown below. Click OK.
Enter the product key and click Next. Or choose evaluation edition and click Next.
Accept the license terms and click Next.
Check to include SQL server product updates and click Next.
The installation will now download the setup files as shown below.
The installation does the pre-requisite checks once again as you can see below.
On the Setup Role page, choose SQL server feature installation and click Next.
Select the required SQL features and click Next.
After the rules are checked as shown below, click Next.
Under Instance Configuration, choose Default instance. You can also define custom instance name. Similarly, you have the option to choose the location where the instance will be stored. I will leave the defaults and click Next button.
Under Disk Space Requirements, the installation will show the disk spaces as shown below.
Under Server Configuration, review the Service Accounts, I will leave the defaults. Here, you can also use Active Directory user for various SQL services.
Under Database Engine Configuration, choose Windows authentication mode. You also have option to choose both windows authentication and SQL server authentication. Then, add the users who will be managing this SQL server and click Next.
Under Error Reporting, review the information and click Next. Likewise, under Installation and Configuration Rules as shown below, verify whether all the rules are passed and click Next.
Under Ready to Install, review the installation information and click the Install button.
After the installation is complete, click Close. You can now start creating databases.
In this way you can install SQL Server 2012 in Windows Server 2012 R2.
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نصب vCenter 5.5 بر روی ویندوز سرور 2012 R2 با SQL Server 2012
نصب vCenter 5.5 بر روی ویندوز سرور 2012 R2 با SQL Server 2012
vCenter server is central place for managing all the vSphere components like ESXi hosts, clusters, virtual machines, virtual machine templates, replication, high availability and so on. With release of vSphere 5.5, VMware has made lot of improvements in vSphere web client. There are two flavors of vCenter server. First – You can install vCenter Server in Windows Operating Systems, Second – vCenter Server Appliance (VCSA) which is based on SUSE Linux platform. There are different pieces of vCenter server that works together. The components are: Single Sign-On, vSphere Web Client, vCenter Inventory Service and vCenter Server. In this post, I will show steps to install vCenter 5.5 in Server 2012 R2 with SQL Server 2012. vCenter needs database to store all the vSphere components data like configuration, statistics, etc. Regarding database options, you can choose either dedicated SQL database Server or Oracle database server for vCenter server, or you can go with default express database.
Install vCenter 5.5 in Server 2012 R2 with SQL Server 2012
Here is our scenario shown below. ESXi hypervisor is already installed in physical machine. There are three virtual machines, MBG-DC01 is a domain controller, MBG-VCENTER01 is a Server 2012 virtual machine – this is where we will install vCenter and MBG-SQL-DB01 is SQL Server 2012. Both vCenter and database server are member of active directory domain.
Minimum hardware and software requirements for vCenter server depends upon installation scenario. So don’t forget to check the requirements. I have already installed SQL Server 2012 in Server 2012 R2 on MBG-SQL-DB01 virtual machine. Because, before installing vCenter, we need to create user account to manage vCenter server and create ODBC database connection. You create user account in Domain Controller and ODBC database connection in SQL server. Then, you can begin installing vCenter 5.5 in Server 2012.
To start the installation, login to vCenter Server, insert the vCenter installation disk and run the install. You have two main option to install vCenter server, simple install or custom install. You can install each components in different server but for now, VMware recommends to install all the components in single server. Here, I will choose simple install as this will be single server installation.
Step 1. In the first page of installation, select Simple Install option and click Install button.
Step 2. Click Next on the Welcome to the vCenter Single Sign-On Page.
Step 3. In End-User License Agreement page, accept the License Terms and click Next.
Step 4. In the Simple Install prerequisite page, the installation will perform prerequisite check as shown below. Then click Next.
Step 5. In the vCenter Single Sign-On Information page, type the password. Notice, the default domain is vsphere.local and you can’t change it. You can change it later when you sign into vCenter server using this username and password.
Step 6. On the Simple Install Configure Site page, type the site name and click Next.
Step 7. On the Simple Install Port Settings page, configure the port number and click Next. The default port number 7444 is fine for single sign on purpose.
Step 8. On the Change destination folder page, browse the destination location to install vCenter Single-Sign on components.
Setp 9. Now review the installation option and click Install button.
Step 10. The installation will now start.
Step 11. The installation of vCenter Inventory Service will also start automatically.
Step 12. You will now be asked for License Key. Enter the license key and click Next.
Step 13. Then installation of vCenter Server will start. Under Database Options, choose, use an existing supported database and clickNext.
Step 14. Click Next on Database Credentials. In this case, the database user is AD integrated.
Step 15. Now enter the vCenter service account information as shown below. This is the local username and password to login to vCenter server. Click Next.
Step 16. Choose Create a standalone VMware vCenter Server instance option and click Next.
Step 17. Review the port settings and click Next. You can edit the port settings here if you need to.
Step 18. Choose the inventory size that suits your environment and click Next.
Step 19. Review the settings and click Next on vCenter Single Sign On Information page. Click Yes for certificate shown.
Step 20. Type the user account for vCenter server administration. You will use this account to login to vCenter server to manage vSphere infrastructure.
Step 21. Review the vCenter Inventory lookup service URL and click Next.
Step 22. Choose the destination folder for vCenter installation and click Next.
Step 23. Click Install button on ready to install page. The installation will now start. If you get stuck in installing directory services, then browse this link for solution. If you get, “Failed to initialize LDAP instance manager” browse this link.
After the installation is completed, you can open vCenter web client and start managing your vSphere infrastructure. Login with theadministrator@vsphere.local user account at first time and then you can add active directory domain and domain user account.
In this way you can install vCenter Server 5.5 in Server 2012 R2 with Database Server 2012.
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پیکربندی Single Sign-on در VMware vCenter 5.5
پیکربندی Single Sign-on در VMware vCenter 5.5
بعد از اینکه vCenter Server را نصب نمودید شما احتمال دارد بخواهید با اکانت کاربری اکتیو دایرکتوری به VCenter لاگین نمایید.
برای انجام این کار
After you’ve installed vCenter server, you might want to authenticate vCenter sign on with Active Directory user accounts. To do so, you need to configure single sign-on in VMware vCenter 5.5, you also need to add user accounts/groups in vCenter.
Configure Single Sign-on in VMware vCenter 5.5
Step 1. Open vSphere web client and login with administrator@vsphere.local user account.
Step 2. Click Administration on the navigation pane. Expand Single-Sign on and click Configuration. Select Identity sources tab.
Step 3. Click Add. Choose Active Directory (Integrated Windows Authentication) on Identity source type option as this is Windows based vCenter server. The domain name will be auto populated. Choose use machine account. Click OK.
Step 4. You can view the identity source on the list as shown below. Now select the domain and click icon to set it as default domain for vCenter. Read the warning and click OK.
Step 5. Now go to, Users and Groups tab on the same navigation pane. Then select Groups tab. Click Administrators group as shown below. Under group members, click Add to add user accounts.
Step 6. Choose the domain from drop down. Select the user, in this case, Administrator. Then click Add. Click OK.
Step 7. Now, navigate to Home > vCenter > Inventory Lists > vCenter Servers. Select the vCenter server. Select Manage tab and clickPermission tab again. Click Add to add domain user to provide full permission to this vCenter server.
Step 8. Add the domain user account, choose Administrator as assigned role and click OK.
You can now login with domain administrator account. If you are getting Cannot Parse Group Information error while logging in with AD Administrator account then try this fix.
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ایجاد کاربر در VMware vCenter
ایجاد کاربر در VMware vCenter
I bet everything went great in your VMware infrastructure, until the company hired a junior admin to help you with the work. Now that’s not a bad thing, but you can’t just give him/her full permissions to your vCenter from the start, because it needs to learn the infrastructure first and get familiar with it. If adding a user to your VMware vCenter infrastructure is a challenge, no worry, I will show you how is done in just a second.
The vCenter server that I will use here is part of a local Microsoft Active Directory domain, so the new user will be a domain user. If you don’t have an AD environment, that’s no problem, you just create the junior admin account on the vCenter server machine; I will show you that too, later. First let’s start by creating the user account in Active Directory, so right-click your OU and choose New > User. Complete the boxes and click Next.
Now choose a password for the junior admin to use and finish the wizard. The account is now created are ready to be used.
If you don’t have an AD environment just create the user account on your vCenter server. Right click Computer, choose Manage, and expand Configuration > Local Users and Groups. Create a new user account by right clicking the Users object and choose New user. On the New user box complete the requirements and clear User must change password at next logon. Click Create.
Now open your vCenter client console and connect to the vCenter server using an administrator account. Once the console is fully opened click the vCenter server name then go to the Permissions tab.
Here right-click and choose Add Permission.
On the Assign Permissions window click the Add button.
Choose your domain from the Domain list and now all the users and groups from the AD domain should appear under Users and Groups. Select the junior admin account we created before and click the Add button. If you want to add another user or group, just select it and click the Add button again. When you’re done click OK.
Back to the Assign Permissions window, we have our junior admin account. The last step is to assign the necessary permissions to this account, and you can do this from the Assign Role box. For the sake of this example just leave it to Read only. If you want this permissions to propagate on all your ESX hosts, folders, Pools etc, leave the Propagate to Child Objects box enabled. Click OK when you’re done.
The account is added in the Permissions tab on the vCenter server, with the rights we just configured.
Now let’s see from a client perspective. Log in to a client computer using the junior admin account and connect to your vCenter server using the same account. I will use a Windows 7 machine on which I installed the vSphere client.
Since the user has read only permissions on the vCenter server, he can see all the vCenter infrastructure. Right click on one of the objects (ESX server, virtual pool, folder etc) and you should see that access is denied for the user to shut down, reboot, create new virtual machine etc.
If you want to be more granular with permissions, you can add the user account on a server level, then the user will only be able to see that specific server. More about vCenter permissions in a future post.
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مقدمه ای بر SQL Server Cluster
مقدمه ای بر SQL Server Cluster
The options for high availability can get confusing. I was lucky enough to begin working with SQL Server clusters early in my career, but many people have a hard time finding simple information on what a cluster does and the most common gotchas when planning a cluster.
Today, I’ll tell you what clusters are, what they’re good for, and why I like to plan out my clusters in a very specific way. I’ll also give an overview of how clustering relates to the AlwaysOn Availability Groups feature in SQL Server 2012, and wrap up with frequently asked questions about clustering SQL Server.
WHAT TYPE OF SQL CLUSTERING ARE WE TALKING ABOUT?
There are lots of types of clusters out there. When we cluster SQL Server, we install one or more SQL Server instances into a Windows Failover Cluster. In this post I’m talking specifically about clustering SQL Server 2005 or later using Windows Server 2008 or later.
Key Concept: A Windows Failover Cluster uses shared storage– typically, this shared storage is on a SAN. When a SQL Server instance is installed on the cluster, system and user databases are required to be on the shared storage. That allows the cluster to move the SQL instance to any server (or “node”) in the cluster whenever you request, or if one of the nodes is having a problem. There is only one copy of the data, but the network name and SQL Server service for the instance can be made active from any cluster node.
Translation: A failover cluster basically gives you the ability to have all the data for a SQL Server instance installed in something like a share that can be accessed from different servers. It will always have the same instance name, SQL Agent jobs, Linked Servers and Logins wherever you bring it up. You can even make it always use the same IPAddress and port– so no users of the SQL Server have to know where it is at any given time.
Here is a diagram of a SQL Server cluster. The cluster is named SQLCLUSTER01. It has two nodes (servers), which are named SQLCLU01NODE01 and SQLCLU01NODE02. People connect to the SQL Server instance at SQLCLU01A\SQL. The instance has been configured on port 1433.
Oh no! There’s been a failure in our environment!
Here’s what happened.
The SQLCLU01NODE01 server crashed unexpectedly. When this happened, the Windows Failover Cluster service saw that it went offline. It brought up the SQL Server services on SQLCLU01NODE02. The SQLCLU01A\SQL instance started up and connected to all the same databases on the shared storage– there’s one copy of the data, and it doesn’t move. As part of the SQL Server startup, any transactions that were in flight and had not committed at the time of the crash were rolled back.
While this automatic failover was occurring, users could not connect to the SQLCLU01A\SQL instance. However, after it came back up they were able to resume operations as normal, and had no idea that a server was still offline.
WHY YOU CARE ABOUT SQL SERVER CLUSTERING
If you’re a business owner, manager, or DBA, you care about clustering because it helps keep your applications online more of the time— when done properly, it makes your database highly available.
Here are some ways that clustering makes your life easier:
- Hardware failures are a nightmare on standalone servers. If a server starts having problems in a failover cluster, you can easily run your SQL Server instance from another node while you resolve the issue.
- Applying security patches on a standalone server can be very tedious and annoying to the business: the SQL Server is offline while you wait for the server to reboot. By using failover clustering, you can apply patches with only brief downtimes for your application as you move your SQL Server instance to a different node.
- Failover clusters can also give you an additional tool in your troubleshooting toolkit. Example: if you start seeing high latency when using storage and you’ve ruled out all the immediate candidates, you can fail to another node to try to rule out if it’s a problem with a per-node component like an HBA.
- Clustering is transparent to the calling application. Lots of things with SQL Server “just work” with clustering, whereas they’re a little harder with other alternatives. With clustering, all of my databases, logins, agent jobs, and everything else that’s in my SQL Server instance fail over and come up together as a single unit— I don’t have to script or configure any of that. I can also cluster my distributed transaction coordinator and fail it over with my instance as well.
GOTCHAS AND NOTES FOR PLANNING A SQL CLUSTER
Know What Clustering SQL Server Doesn’t Do
The first gotcha is to be aware of what a failover cluster won’t help you with.
Clustering won’t improve your performance, unless you’re moving to more powerful servers or faster storage at the same time you implement clustering. If you’ve been on local storage, don’t assume moving to a SAN means a nirvana of performance. Also, clustering doesn’t guarantee that everything involved in your SAN is redundant! If your storage goes offline, your database goes too.
Clustering doesn’t save you space or effort for backups or maintenance. You still need to do all of your maintenance as normal.
Clustering also won’t help you scale out your reads. While a SQL Server instance can run on any node in the cluster, the instance is only started on one node at a time. That storage can’t be read by anyone else on the cluster.
Finally, clusters won’t give you 100% uptime. There are periods of downtime when your SQL Server instance is “failing over”, or moving between nodes.
Invest Time Determining the Right Naming Convention
You have a lot of names involved in a cluster: a name for the cluster itself, names for each of the servers in the cluster, and names for each SQL instance in the cluster. This can get confusing because you can use any of these names later on when connecting with Remote Desktop– so if you’re not careful, there may be times when you’re not entirely sure what server you’re logged onto! I have two general rules for naming:
First, make sure it’s obvious from the name what type of component it is– whether it’s a cluster, physical server, a SQL Server instance, or a Distributed Transaction Coordinator. I also recommend installing BGINFO to display the server name on the desktop for every server in the cluster.
Second, name everything so that if you later add further nodes or install another SQL Server instance onto the cluster, the names will be consistent.
Avoid Putting Too Many Nodes in One SQL Cluster
I prefer to have only two or three nodes in a cluster. For example, if I need to cluster five SQL Server instances, I would put them in two failover clusters.
This requires a few extra names and IP Addresses overall, but I prefer this for management reasons. When you apply patches or upgrades, you must make sure that each service on your cluster runs on each node successfully after you’ve applied the change. Having a smaller cluster means you don’t need to fail your instance over as many times after a change.
Don’t Assume Your Applications Will Reconnect Properly After Failover
Even though your SQL Server instance will come up with the same network name and IPAddress (if not using DHCP), many applications aren’t written to continue gracefully if the database server goes offline briefly.
Include application testing with your migration to a failover cluster. Even though the application doesn’t know it’s talking to a cluster (it’s a connection string like any other), it may not reconnect after a failover. I worked with one application where everything worked fine after a failover, except web servers stopped writing their log data to a database because they weren’t designed to retry after a connection failure. The data was written asynchronously and didn’t cause any failures that impacted users, but the issue wasn’t noticed immediately and caused the loss of some trending data.
“Active Active” Can Be Useful
My ideal cluster layout to work with is a two node cluster with identical hardware and two SQL Server instances on it. This is commonly called “Active Active” clustering, but that term is technically a no-no. Officially this is called a “Multi-Instance Failover Cluster.” Not quite as catchy, is it?
Many people think the ideal situation is to put their most important SQL Server instance on a two node cluster and leave the second node ready, waiting, and idle. So, why do I want a second SQL Server instance?
I like to put my critical, heavy hitter database on one of those instances in the cluster. I then want to take a couple of less critical, less busy databases and put them on the second instance. The perfect examples are logging databases. There are two requirements for these databases: first, they can’t require a large amount of memory or processor use to run well, because I absolutely have to know that these two instances can run successfully at peak load on a single node if required. Second, the databases on the “quiet” instance shouldn’t cause the whole application to go offline if they aren’t available.
Why do I like having a “quiet” instance? Well, whenever I need to apply updates to Windows or SQL Server, this is the canary I send into the coal mine first. You can perform rolling upgrades with failover clusters, which is great. But it’s even better to know that the first instance you fail over onto an upgraded node won’t take absolutely everything down if it has a problem.
Notes: Because of licensing costs, this option won’t always be realistic. If you go this route you have to make sure everything can stay within SLA if it has to run on a single node at your busiest times– don’t overload that “quiet” instance!
Re-Evaluate your SQL Server Configuration Settings
Revisit your configuration settings as part of your planning. For example, on a multi-instance cluster, you use the minimum memory setting for SQL Server to configure how your instances will balance their memory usage if they are on the same node.
DO I HAVE TO USE CLUSTERING TO USE AVAILABILITY GROUPS IN SQL SERVER 2012?
This is an interesting question– don’t let it confuse you. We have a very cool new feature calledAvailability Groups coming in SQL Server 2012, which does offer awesome scale-out read functionality. You’ll read in many places that it “requires Failover Clustering.”
This is true. In order to use the Availability Group feature in SQL Server 2012, the Failover Clustering feature must be enabled in Windows. If you’re using Windows Server 2008 or prior, this feature is only available in Datacenter and Enterprise edition of Windows Server, so that feature isn’t free. This feature is now included in Windows Server 2012 for all editions.
But wait, there’s a catch! Even though you’re enabling the Failover Cluster feature, you are NOTrequired to have shared storage to use Availability Groups. You have the option to use a Failover Cluster in an Availability Group, but you can also run your Availability Groups with entirely independent storage subsystems if you desire. The feature is required because no matter what, Availability Groups will use parts of the Failover Clustering feature to manage a virtual network name and IP Address.
FREQUENTLY ASKED QUESTIONS FOR CLUSTERING SQL SERVER
Q: Can I install every SQL Server component on my cluster?
A: Nope. SQL Server Integration Services is not “cluster-aware” and can’t fail back and forth with your cluster.
Q: How long does it take to fail over?
A: There are several factors to consider in failover time. There’s the time for the SQL Server Instance’s service to go down on one node, be initiated on another node, and start up. This time for instances to start and stop includes normal database recovery times. If you need to keep failovers within an SLA, you’ll want to test failover times in a planned downtime, but also estimate in how long failover mightbe if it happened at peak load.
Q: Can I cluster a virtualized server?
A: Yes, you can create failover clusters with virtual servers with VMware or Hyper-V, and install SQL Server into it. I think this is great for learning and testing, but I’m not crazy about this for production environments. Read more here.
Q: Why do you make such a big deal about the shared storage?
A: Because not everyone has robust shared storage available. You want to make sure you’re using shared storage that has redundancy in all the right places, because in a failover cluster shared storage is a single point of failure, no matter how magical the SAN seems. This also means that if your data is corrupted, it’s going to be corrupted no matter which node you access it from.
Q: What’s the minimum number of nodes in a failover cluster?
A: One. This is called a single-node cluster. This is useful for testing purposes and in case you have a two node cluster and need to do a work on a node. You can evict a node without destroying the cluster.
Q: Can I use geo-clustering for Disaster Recovery?
A: Yes, but it requires some fancy setup. Most SQL Server clusters are installed in the same subnet in a single datacenter and are suitable for high availability. If you want to look into multi-site clustering, “geo-clustering” became available with SQL Server 2008, and is being enhanced in SQL Server 2012. Note: you’ll need storage magic like SAN replication to get your Geo-cluster on.
Q: Does it matter which version of Windows I use?
A: Yes, it matters a lot. Plan to install your Windows Failover Cluster on the most recent version of Windows Server, and you need Enterprise or Datacenter edition. If you must use an older version of Windows, make sure it’s at least Server 2008 with the latest service packs installed. The Failover Clustering Component of Windows was rewritten with Server 2008, so if you run on older versions you’ll have fewer features and you’ll be stuck chasing old problems.
Q: What is Quorum?
A: Quorum is a count of voting members— a quorum is a way of taking attendance of cluster members who are present. The cluster uses a quorum to determine who should be online. Read more about quorum here.
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برطرف کردن مشکل device manager error code 39 در USB Controller
برطرف کردن مشکل device manager error code 39 در USB Controller
What will you do if all the USB ports of your Desktop/Notebooks stopped working all of the sudden? At first, we might think the issue is with USB port and needs to replace the corresponding hardware device to solve the issue.
Code 39 is a common error message for USB controllers. Uninstalling and reinstalling USB drivers may not solve this issue. Code 39 may also show the error message “Windows cannot load the device driver for this hardware. The driver may be corrupted or missing. (Code 39)”.
Code 39 error may be shown on USB devices like “Standard enhanced PCI to USB host controller” and “Standard OpenHCD USB host controller”.
I found that Code 39 errors with USB controller is shown when an invalid registry values are saved in Windows Registry. We need to check whether registry values like “UpperFilters” and “LowerFilters “ is listed under {36FC9E60-C465-11CF-8056- 444553540000} as this entries will prevent the USB devices to work properly.
Solve Error code 39 on USB Controller:
1. Click Start, Run and type Regedit to Open Registry Editor Or Click Start, type regedit in search window and open Registry Editor.
2. Registry Editor window will open now.
3. Click on HKEY_LOCAL_MACHINE to expand it.
4. Under HKEY_LOCAL_MACHINE, click on SYSTEM and expand it.
5. Under System, click on CurrentControlSet and expand it.
6. Under CurrentControlSet, click and expand Control
7. Under Control, click and expand Class
8. Under Class, find and select {36FC9E60-C465-11CF-8056- 444553540000}
9. Single click on {36FC9E60-C465-11CF-8056- 444553540000} (no need to expand it)
10. Then check the right pane window of the Registry Editor for any entry with name UpperFilters or LowerFilters
Note: As I am not experiencing this issue when I took above said screenshots, you will not find the registry entry UpperFilters or LowerFilters listed in below provided image.
11. On the right pane of Registry Editor, please check whether any entry with name “UpperFilters” or “LowerFilters” is listed, if you find any, please right click and delete it.
12. Now disconnect all the USB devices connected to the computer and uninstall each USB entry from Device manager. Then restart the Notebook/Computer.
– See more at: http://www.tricksguide.com/solve-device-manager-error-code-39-on-usb-controller.html#sthash.iQ3HnwPm.dpuf
Byadmin
پیکربندی شبکه بیسیم ایمن در مودم BSNL Nokia Siemens SL2_141
پیکربندی شبکه بیسیم ایمن در مودم BSNL Nokia Siemens SL2_141
Configuring BSNL Nokia Siemens SL2_141/SL2-141 Broadband Modem is pretty easy, if you have not yet configured the modem to enable Internet through LAN/WLAN (Wi-Fi), then follow the steps mentioned in our two previous articles.
1. Setup Internet and Wireless Internet on BSNL Siemens SL2_141 ADSL Modem
2. Configure Wireless LAN on BSNL Siemens SL2_141 Broadband Modem
How to secure Wireless LAN on your BSNL Siemens SL2_141 Modem
We have already configured Wireless on your Modem. So you do not need to change any settings for the Wireless (Wi-Fi) to work. But you might have noticed that the WLAN we configured is unsecured. It means the WLAN you configured is not encrypted Or not password protected. In this Post, we will show you how to password protect Wireless LAN!.
1. Open Internet Explorer, type (Or type 192.168.1.1) and press the Enter key on the keyboard. Now a popup screen asks you to enter User name and password to configure your Siemens SL2_141 broadband modem as we shown below.
2. Enter below said user name and password (Use the default factory user name and password) and click OK.
User name: admin
Password: admin
3. Once you login, we will enter modem configuration page as shown below.
4. Click on Wireless at the left pane of the window.
5. Click on Basic at the left pane of the window. Now you are at Wireless – Basic Page as shown below.
6. Ensure that Enable Wireless check box is checked (tick mark should be there). (Note: In future, if you wish to disable Wireless, you can uncheck this box).
7. Enter a name for Wireless LAN in SSID box, you can enter whatever you like, (E.g: SiRu Wireless).
8. Select Country as UNITED STATES. Click Save/Apply button.
9. Once you are done, click on Security at the left pane of the Window. It will open Wireless – Security page. 10. Change the settings as shown below, also refer below said screenshot for more information.
Select SSID: The name of your Wireless LAN (SSID). (E.g: SiRu Wireless)
Network Authentication: WPA-PSK
WPA Pre-Shared key: abcdefghijk (You can use any password that you like)
WPA Encryption: TKIP
WEP Encryption: Enabled
Encryption Strength: 64 bit
Current Network Key: 2
Network Key 2: siraj (enter any 5 character word that you like)
11. Click on Save/Apply button.
12.The modem will reboot now. If you are currently connected to the Wireless LAN, then you need to manually disconnect it and reconnect to the new Wireless LAN.
The WPA Pre-Shared key I have used in this tutorial is abcdedfghijk. You need to understand that you can use any password (WPA Pre-Shared key ) that you like. Please ensure that you remember the password as you will be prompted to enter the password when you connect to the Wireless LAN. This password and encryption will secure your Wireless LAN and no one will be able to access Wireless Internet without knowing your Internet Password.
How to connect to Secure Wi-Fi (WLAN) from your computer?
Most of the Notebooks and Desktops are shipped with Wireless capabilities. A wireless card installed on your computer enable you to access Internet without hooking a cable to a Modem or to a Router. Now let us check how do we connect to a Secured Wi-Fi (WLAN) from a computer.
1. Turn ON WLAN on your Notebook/Desktop. In most of the computers, it is a switch or button you can press to enable WLAN.
2. Now Search for the Wireless Network. Below said screenshot is taken from my Vista based Notebook.
3. Select the Security Enabled network name (E.g.: SiRu Wireless) and click on Connect button.
4. As the network we setup is a Secured network, below said message will appear.
5. Enter the Password (E.g.: abcdefghijk) (Note: I hope you remember the password)
6. Click on Connect button
6. Yes, now it is connected. Click on Close button.
7. Congratulations. You are successfully connected to the Secured Wireless Internet.
– See more at: http://www.tricksguide.com/how-to-configure-a-secured-wireless-lan-with-bsnl-nokia-siemens-sl2_141-broadband-modem.html#sthash.MnYsH82w.dpuf