Virtual desktop infrastructure's appetite for storage isn't easily quelled. When choosing VDI storage hardware, IT decision makers need to think about their organization's size, needs and I/O demands, as well as how the storage system they select will react in the event of a failure.
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Beyond the price of storage -- an obvious consideration with any purchase -- some essential factors to take into account while shopping for VDI storage hardware include:
- Capacity. The product you choose needs sufficient capacity to accommodate your virtual desktops, while also having room to support growth.
- Throughput. Often the connectivity between a storage device and a host server forms a bottleneck. The product you choose needs to support connectivity that's fast enough to deliver adequate throughput.
- Disk I/O performance. The storage device must be able to deliver disk I/O at a rate that's sufficient to meet the demands of the virtual desktops.
- Fault tolerance. VDI storage hardware needs to be fault tolerant, so that the failure of a hard disk or other component won't result in an outage.
VDI storage hardware options
When reviewing the products on the market, consider your organization's storage needs. Some of these products are best suited to small VDI deployments and others are designed for large projects.
Drobo. One potential offering is Drobo Inc.'s Drobo B800fs, which can accommodate up to 24 TB of raw storage (up to eight 3 TB SATA drives). Realistically, however, most organizations using this VDI storage hardware would probably opt to configure the unit as a RAID 6 array. Doing so protects against the failure of two drives, but it also reduces the overall maximum capacity to 18 GB.
The Drobo B800fs features twin gigabit Ethernet ports that can be bonded together to provide an overall speed of 2 gigabits. As an alternative, you can reserve one of the Ethernet ports for failover purposes and the second Ethernet port as a dedicated pipe for backing up the storage array.
QNAP. The Windows Active Directory. It can't be joined to Active Directory, but it features a Web interface you can use to assign file and folder permissions directly to Active Directory (or LDAP) user accounts. The appliance also supports SMB/CIFS, NFS and AFP file-sharing protocols.
One area in which the QNAP TS-869 Pro exceeds the Drobo B800fs' capabilities is with RAID configuration. The Drobo appliance only supports RAID Levels 5 and 6, but the QNAP TS-869 Pro supports RAID 0, 1, 5, 6 and 10. You can also set up the appliance as multiple storage arrays, so one hard drive can be designated as a hot spare. The hot spare can replace a failed drive in any of the defined RAID arrays. Finally, the appliance supports multiple network interface card (NIC) bonding modes to facilitate load balancing, fault tolerance, failover and connectivity to multiple subnets.
NetApp. NetApp Inc. offers higher-end VDI storage hardware with its NetApp FAS6200 Series Enterprise Storage System. When operating in an active/active dual-controller configuration, the system offers a maximum capacity of 4,320 TB. To achieve this monstrous capacity, the system supports up to 1,440 drives.
NetApp's system features eight 10 gigabit Ethernet ports and can accommodate between eight and 32 8-gigabit Fibre Channel host bus adapters. The system also supports a maximum 16 TB flash cache size and up to 192 GB of memory.
GreenBytes. GreenBytes offers vIO, a virtual storage appliance version of its IO Offload Engine. The appliance supports NFS and iSCSI and is designed to work with a PCIe-based Flash card, local solid-state drive storage or Flash-based storage controller. It provides I/O offload for 100 or more persistent or nonpersistent virtual desktops, plus it supports asynchronous replication for backup and recovery.
TeraStation Pro 8. Buffalo Technology Inc.'s TeraStation Pro 8—TS-8VHL/R6 is a lower-end VDI storage hardware that might be an option for companies deploying small-scale VDI. This appliance is available in a 16 TB configuration (TS-8VH16TL/R6) or a 24 TB configuration (TS-8VH24TL/R6) and can accommodate up to eight SATA drives in front-loading, hot-swappable drive bays. The drives can be used in a variety of RAID configurations, including RAID 0, 1, 5, 6, 10, 50, 51, 60 and 61 and JBOD.
Network access is provided through twin gigabit Ethernet adapters, which offer jumbo frame support. You can assign permissions to files and shares to Active Directory users through a Web interface. The appliance also supports many different protocols for file sharing, including the following:
- CIFS/SMB (Common Internet File System/Server Message Blocks)
- AFP (Apple Filtering Protocol)
- HTTP/HTTPS (Hypertext Transfer Protocol/Secure Hypertext Transfer Protocol)
- FTP/SFTP/FTPS (File Transfer Protocol/Secure File Transfer Protocol/FTP Secure)
- NFS (Network File System).
One potential downside to the TeraStation Pro 8—TS-8VHL/R6 in a VDI environment is that it does not offer iSCSI support. Although iSCSI is not a necessity for every VDI product on the market, some products require storage arrays to be connected through either iSCSI or Fibre Channel.