Enabling the Next- Generation File Server with SMB 3. Every organization uses Server Message Block (SMB) in some form to access storage. It might be to access logon scripts, to access and use software- installation media, or for users to access their documents and MP3 collections. But what SMB hasn't been used for is a file- level protocol (in which the client doesn't directly access the disk blocks but instead is served files) for enterprise applications to access remote storage. When it comes to communicating with storage for enterprise workloads, block- level technologies (in which the server can communicate directly with disk blocks) such as i. SCSI and Fibre Channel (and maybe NFS for non- Windows workloads) have been top on the list. ![]() ![]() We can start Terminal Services by running the command given below.
![]() For a user editing a Microsoft Power. Point document from an SMB share, portions of the document are cached locally, and occasionally the user clicks Save. If the SMB file- server experiences a problem such as rebooting, or if it's clustered and the file share moves to another node in the cluster, the user loses the handle and lock to the file—but without any real impact. The next time the user clicks Save, everything is re- established and no harm is done. Now consider Hyper- V storing a virtual machine (VM) on an SMB file share that experiences a problem. The file share moves to another node in the cluster. First, the Hyper- V server waits for the TCP timeout before realizing that the original connection has gone. This could mean 3. VM. But Hyper- V has also now lost its handles and locks on the virtual hard disk (VHD), which is a major problem. Whereas user documents might be used for a few hours, enterprise services such as a VM or database expects handles on files to be available for months without interruption. For Windows Server 2. Microsoft wanted to make SMB a file- level storage protocol that could be used for crucial enterprise workloads such as Microsoft Hyper- V and SQL Server. To make this shift, some major changes to the SMB protocol were required. Rather, it will be part of a cluster, to provide high availability. For a clustered file service, a single cluster node typically mounts the LUN that contains the shared file system and offers the share to SMB clients. If that node fails, then another node in the cluster mounts the LUN and offers the file share. However, the SMB client then loses its handles and locks. It does so by enabling a share to move between nodes in a manner that is completely transparent to the SMB clients, maintaining any locks and handles that exist as well as maintaining the state of the SMB connection. SMB Transparent Failover ensures that enough context exists to bring the SMB connection state back to an alternate node if a node fails, allowing SMB activities to continue without the risk of error. The LUN must be mounted on a new node in the cluster. But the Failover Clustering team has done a huge amount of work around optimizing the dismount and mount of a LUN to ensure that it never takes more than 2. That sounds like a long time, but it's the absolute worst- case scenario, involving large numbers of LUNs and tens of thousands of handles. For most common scenarios, the time would be only a couple seconds. And enterprise services such as Hyper- V and SQL Server can handle an I/O operation of 2. HyperTerminal Windows 7, 8, 10, XP, and Vista terminal emulation software is now available. Some uses of HyperTerminal Private Edition: Use a TCP/IP network to. Windows Vista Computer Configuration-> Administrative Templates-> Windows Components-> Terminal Services-> Terminal Server-> Security. Windows 7, Windows 8, Windows 8. ![]() In a typical planned scenario (e. But if a node crashes, there is no client notification. Rather, the client sits and waits for TCP timeout before taking action to re- establish connectivity—a waste of resources. Although an SMB client might have no idea that the node it's talking to in the cluster has crashed, the other nodes in the cluster know within a second, thanks to the various Is. Alive messages that are sent between nodes. The Witness Service essentially allows another node in the cluster to act as a witness for the SMB client. If the node that the client is talking to fails, the witness node notifies the SMB client, allowing the client to connect to another node and minimizing the service interruption to a couple seconds. The conversation looks something like the following (but in 1s and 0s and with less personality): SMB Client to Server A: . Also, I am part of a cluster. Servers B, C, and D are also in the cluster. ![]() Have a nice day. When you create a new share on a Windows Server 2. SMB Transparent Failover is enabled automatically. A wizard guides the process of creating a new share in a Windows Server 2. The first decision is which type of share you are creating. The answer simply helps to set some default options for the file share, as shown in Figure 1. You might be familiar with this as a challenge for Windows Server 2. Hyper- V when moving VMs between nodes. The problem stems from the fact that NTFS is a shared- nothing file system and can't be accessed concurrently by multiple OS instances without the risk of corruption. This problem was solved with the introduction of cluster shared volume (CSV) support in Windows Server 2. R2. CSV allows all nodes in a cluster to read and write to a set of LUNs simultaneously, using some clever techniques and removing the need to dismount and mount LUNs between nodes. This new option is targeted for use only when sharing application data such as SQL Server databases and Hyper- V VMs. The traditional style of a general- use file server is still available for non- application data, as shown in Figure 3. Because this storage is available to all nodes in the cluster, all those nodes also host the file share. Therefore, SMB client connections are distributed over all the nodes instead of just one. If a node fails, no work is involved in moving the LUNs, offering an even better experience and reducing interruption in operations to almost zero. This reduction is crucial for the application- server workloads at which this Scale- Out File Server is targeted. Typically, when a general- use File Server is created, you must give the new cluster file server a Net. BIOS name and unique IP address as part of the configuration. That IP address must be hosted by whichever cluster node is currently hosting the file server. With Scale- Out File Servers, all nodes in the cluster offer the file service. Therefore, no additional IP addresses are required. Instead, the IP addresses of the nodes in the cluster are used via the configured Distributed Network Name (DNN). Essentially, when the SMB client initiates connections, it initially receives a list of all the IP addresses for the hosts in the cluster. The client picks one with which to initiate the SMB session and then uses only that node, unless the node experiences a problem. If that happens, the client converses with an alternate node, except when leveraging the Witness Service. But there are other types of failure, such as a connection failure. To counteract this type of issue, you can use technologies such as Microsoft Multipath I/O (MPIO), which provides multiple paths from server to storage. SMB 3. 0 introduces SMB Multichannel, which allows an SMB client to establish multiple connections for a single session, providing protection from a single connection failure and boosting performance. After the initial SMB connection is established, the SMB client looks for additional paths to the SMB server. If multiple network connections are present, those additional paths are used. The use of SMB Multichannel is apparent when monitoring a file copy operation, because only one connection's worth of bandwidth is used initially but doubles as the second connection is established, continues to increase with the third connection, and so on. If a connection fails, other connections continue the SMB channel without interruption. In the output that Figure 4 shows, I can see that I have only one connection to my server. If I run the Get- Smb. Multichannel. Connection cmdlet from the client, the output shows all the possible paths over which the server can accept connections, as shown in Figure 5. This confirms that I am using the one path that can be used: remote address 1. Figure 6 shows. The answer is no. The SMB client receives a single IP address for one node in the cluster, and all connections are to that node. All SMB sessions for that cluster from one SMB client will always go to the same node in the cluster. Remember, this isn't a problem because a highly available cluster typically has hundreds if not thousands of connecting SMB clients. The load will be distributed fairly evenly throughout the cluster. Many data centers have shifted from 1. Gbps to 1. 0Gbps. But as data centers adopt 1. Gbps, the processor in the server becomes a performance bottleneck. A single TCP connection can be processed by only one processor core, which can't handle 1. Gbps and typically restricts the bandwidth. This is where Receive Side Scaling (RSS) comes into play. With RSS, a single network interface is split into multiple receiving connections, each of which can be serviced by a separate processing core. Therefore, the full bandwidth can be utilized. Most modern server network adapters automatically support RSS. To determine whether your hardware supports RSS, run the Get- Smb. Multichannel. Connection cmdlet, as shown in Figure 7. This is the default for Windows Server 2. RSS- capable network cards. The first line of the output shows the connection count per RSS network interface.) You can change this value, but the number wasn't picked randomly. Microsoft went through much testing on 1. Gbps connections and found that four connections produces the most gain; more than four connections brings diminishing returns. However, if you have connections larger than 1. Gbps, then increasing this value might benefit you. Network adapters that support RDMA can bypass most of the network stack to communicate directly, avoiding load on the host servers. The Get- Smb. Multichannel. Connection cmdlet that I referred to earlier will show whether the network adapter supports RDMA.
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