PFecY.jpg' alt='Enable Virtualization Patch' title='Enable Virtualization Patch' />Welcome to the Citrix Community page where you can connect with experts and join the conversation about Citrix technologies. Storage Spaces Direct in Windows Server 2. Virtualization Review. In Depth. Storage Spaces Direct in Windows Server 2. Microsofts first attempt at creating a software defined storage platform wasnt a big hit. ScaleXtreme, now a part of Citrix, is a leading provider of enterpriseclass cloudmanagement solutions for automating the delivery and management of IT services. Bitdefender Gravity Zone Security for Virtualized Environments SVE is the platformneutral solution designed for todays complex datacenters. InDepth. Storage Spaces Direct in Windows Server 2016. Microsofts first attempt at creating a softwaredefined storage platform wasnt a big hit. Its updated version just might be. One of the most difficult things in designing IT infrastructure is to get storage right. Think about it Most server applications come with a minimum and recommended amount of memory and CPU capacity. But how often do you see 2. IOPS required per user, or, average storage throughput required is 2. Mbps Add virtualization to the mix, and housing many virtual machines VMs on the same server, all with different storage access patterns, and it can get messy. Microsoft provided Storage Spaces in Windows Server 2. R2 as a first building block for software defined storage SDS. Windows file servers sharing out storage over the SMB 3. SAS attached external storage chassis with hard disk drives HDDs and solid state drives SSDs in tiered storage, provided an alternative to costly SANs while being easier to set up and manage. Despite that, Storage Spaces wasnt a huge success, mainly because traditional vendors didnt want to sell cost effective storage they wanted to sell expensive SANs. Another issue was that Storage Spaces only fitted medium to large deployments where three or four separate servers, along with shared disk trays, made financial sense. In Windows Server 2. Storage Spaces Direct S2. D. Instead of using external disk trays, internal storage in each server is pooled together. This makes scaling easier Simply add another server when you need more storage. It also opens the options for different types of storage, such as cost effective SATA SSDs and HDDs as well as SAS and non shareable data storage such as NVMe flash storage accessed via the PCIe bus instead of SATASAS. In short, S2. D is Microsofts response to VMwares v. SAN. In this article, Ill look at how S2. D works, how it can be deployed, fault tolerance, networking and monitoring. BEHIND THE SCENES IN S2. DThere are two modes in which you can deploy S2. D disaggregated or hyper converged. The contents of this chapter are not required to use VirtualBox successfully. The following is provided as additional information for readers who are more familiar. Simplify thirdparty software patch management. Create before and after deployment package scenarios to help ensure complicated patches such as. Learn how you can get around the Windows client RDP oneconcurrent user limitation in order to enable remote desktop connections for multiple users. VMware_Tools_Properties.png' alt='Enable Virtualization Patch' title='Enable Virtualization Patch' />In a larger deployment, youll probably want to scale your storage independently of your compute hosts youll have storage clusters up to 1. VMs or SQL Server databases. In smaller deployments, you might want to minimize the number of physical hosts and thus might opt for hyper converged where each host has local storage that make up part of the pool, as well as the Hyper V role for running VMs. S2. D will automatically use the fastest storage SSD or NVMe in your servers for caching. This is a dynamic cache that can change the drives it serves based on changes in storage traffic or SSD failure. The overall limit today in a cluster is 4. Storage Spaces. Note that the caching is real time, unlike the job based optimizing once per night caching that Storage Spaced used. Microsoft recommends at least two cache devices SSD or NVMe per node. When youre architecting an S2. D system, plan for approximately 5. GB of memory on each node per 1. TB of cache storage in each node being used. The new file system in Windows Resilient File System Re. FS has come of age and is now the recommended option for S2. D, as well as for Hyper V storage in general. The only main feature missing compared to NTFS is deduplication, but this is coming. If you have three or more nodes in your cluster, S2. D is fault tolerant to the simultaneous loss of two drives or two nodes. This makes sense, because in a shared nothing configuration like S2. D youll need to take servers down for maintenance or patching regularly, and when you have one node down for planned downtime, you need to be able to continue working if another node fails in an unplanned outage. In a two node cluster, of course, its only resilient to the loss of a single drive or node. Two node clusters use two way mirroring to store your data, providing 5. TB of SSDHDD to be able to use 8. TB. A three node defaults to three way mirroring, which has excellent performance but low disk utilization at 3. TB and use 5. TB. Once you get to four nodes, however, things start to get very exciting. Here you can use erasure coding parity similar to RAID 5, which is much more disk efficient 6. Microsoft uses a standard Reed Solomon RS error correction. The problem with parity, however, is that its very expensive for write disk operations each parity block must be read, modified and the parity recalculated and written back to disk. Microsoft solves this problem when youre running Re. FS by combining a three way mirror using about 1. Essentially the mirror acts like an incoming write cache, providing very fast performance for VM workloads. The data is safe because its been written to three different drives on three different servers, and once the data can be sequentially arranged for fast writing its written out to the erasure coding part of the volume. Microsoft calls this accelerated erasure coding, although some articles refer to it as Multi Resilient Volumes MRV. Picking a resiliency scheme depends on your workloads. Hyper V and SQL Server work best with mirroring, parity is more suitable for cold storage with few writes and lots of reads, while MRV excels for backup, data processing and video rendering workloads. As a side note, neither erasure coding nor mirroring in Storage Spaces and S2. D has anything to do with old style Windows Server software RAID. It spreads the data in slabs across all available drives, providing outstanding performance due to parallelism for both read and write operations. In larger clusters 1. Microsoft utilizes a different parity scheme called Local Reconstruction Codes LRC, which is more efficient when you have lots of nodes and drives. Table 1 shows the disk utilization you can expect based on number of nodes. The left hand table shows number of nodes and a combination of HDD and SSD, and the right hand table shows an all flash configuration. Click on image for larger view. Table 1. Disk utilization in Storage Spaces Direct. If you have servers in multiple racks or blade servers in chassis, you can tag nodes in a S2. D cluster with identifying information, so if you have a drive fail itll tell the operator exactly where to go down to the slot number and serial number for both server and disk to swap it out. S2. D will also spread the data out, making the setup tolerant to a rack or chassis failure. Office Compatibility Patch. Unlike Storage Spaces, the process for replacing a drive is very straightforward. As soon as S2. D detects a drive failure, it will start rebuilding a third copy of the failed drive data on other drives in parallel, shortening the time to complete the repair. Once you replace the failed drive, S2. D will automatically detect this, as well, and rebalance the data across all drives for the most efficient utilization. Youll want to set aside about two disks worth of storage for these disk repairs in planning your storage capacity. Microsoft has demonstrated 6 million read IOPS from a single S2. D cluster all flash, which should provide plenty of headroom for most VM deployments. NETWORKING FOR S2. DStorage Spaces requires separate networks for host to storage cluster traffic, a separate network for cluster heartbeat, and yet another network for VM to VMClient traffic. In a hyper converged scenario in Windows Server 2. NICs for fault tolerance using Switch Embedded Teaming SET, then use Qo.