September 17, 2014

Storage Changes in VMware vSphere 5

VMware officially launched their next-generation (version 5) enterprise server virtualization product line this week under the “vSphere 5″ name. As I’ve been doing for the last few major VMware releases, I’m focusing this post on the storage changes present in vSphere 5.

For more information on earlier updates, see my articles:

One first step is VMware’s whitepaper, “What’s New in VMware vSphere 5.0 – Storage“.

Licensing and Availability of Features

VMware has once again changed the licensing and pricing model, throwing the Internet into a tizzy:

  • “Advanced” has been eliminated, moving up to “Enterprise”
  • Pooled vRAM entitlements work across the entire vCenter environment
  • New features like Policy-Driven Storage and Storage DRS (along with SIOC) are exclusive to “Enterprise Plus” licenses
  • VAAI, PSP multipathing, and Storage vMotion are only found in “Enterprise”
  • Thin Provisioning and VADP are available regardless of edition

VMware mucked with vSphere licensing again...

Major New vSphere 5 Storage Features

Storage DRS

Storage DRS is the world’s worst-kept secret, with everyone and his brother talking about it for over a year. Like the existing VM DRS capability, Storage DRS creates resource clusters and automatically moves VMs between them. Storage DRS uses utilization and performance metrics to make the call, and has three modes of operation. It sounds awesome, but it’s an Enterprise Plus-only feature.

Storage APIs – Storage Awareness (VASA)

There’s not much information presently, but a VAAI companion is introduced in vSphere 5: The vSphere Storage APIs for Storage Awareness (VASA) is a communication mechanism for vCenter to detect array capabilities like RAID Level, Thin Provisioning State, Replication State, etc. This will come in handy for all the other features in vSphere 5, especially policy-driven storage!

Policy-Driven Storage

Another new Enterprise Plus feature is Policy-Driven Storage. This allows storage tiers to be defined in vCenter based on SLA, performance, and other metrics which are used during provisioning, cloning, Storage vMotion, and Storage DRS. It leverages VASA for metrics and characterization and supports all arrays in the HCL, regardless of whether they’re NFS, iSCSI, or FC. It includes easy compliance status reporting in vCenter as well.

FCoE Software Initiator

Those of us “in the know” about storage expected VMware to add software FCoE support, so it’s no surprise that they did. This dramatically expands the potential FCoE footprint from just the few CNAs already supported in vSphere 4. It appears to be based on Intel’s OpenFCoE, since it shows up as “Intel Corporation FCoE Adapter” in the GUI!

vSphere Storage Appliance (VSA)

VMware enters the virtual storage appliance (VSA) market with their own offering, the vSphere Storage Appliance (also called VSA). Aimed primarily at the SMB market, it’s actually fairly clever, replicating storage between two or three nodes in a cluster for high availability and using NFS for access rather than iSCSI. And unlike the Celerra UBER that so many techies loved, the VMware VSA is ready for production use!

Existing Storage Features Enhanced in vSphere 5

VMFS 5

VMFS has been improved for scalability and efficiency, but the 2 TB limit on VMDKs remains (except for physical RDM). Only storage geeks like me need to worry about the specifics, but suffice to say that VMFS 5 requires less tuning and worrying and ought to scale and perform better thanks to increased maximums and leveraging the Atomic Test and Set (ATS) technology also used in VAAI. For newly-created volumes, there’s no more block size tuning, and alignment issues are addressed.

Storage APIs – Array Integration (VAAI 2)

See also VMware VAAI Storage Array Support in Plain English

VAAI has been revved, bringing back Thin Provisioning Stun (the AWOL “fourth primitive”) and adding NFS support.

There are now five block primitives for VAAI, depending on if you count thin space reclaim. This is really more of a bug fix than anything, since most folks assumed that the existing thin support already reclaimed deleted VMs and vMotioned VMDKs. I’m more interested in the addition of SCSI UNMAP in addition to WRITE_SAME! There’s also some additional T10 support, though I’m not clear on what it is or where it works.

We’ve also got VAAI for NFS environments now. NAS had sweet thin provisioning support even before block datastores, but the new Reserve Space command adds thick provisioning if that’s what you like. We’ve also got Full File Clone, which is like Full Copy for NFS but doesn’t work with Storage vMotion. And there’s some Extended Stats API to bring in more detail on file status. I also hear there’s an API for Native Snapshot Support, but it’s not widely discussed. Finally, note that NFS plugins come from vendors, not VMware as is the case for block VAAI.

Storage I/O Control

SIOC is enhanced for use in Storage DRS environments, becoming aware of the new datastore clusters. It also gets NFS support, and presumably uses VASA for metrics. But it’s still only available with Enterprise Plus licenses.

iSCSI Initiator GUI

The solid vSphere iSCSI initiator gets a friendly GUI for configuration. I like friendly iSCSI GUIs – just ask Microsoft!

Storage vMotion

The mechanism behind Storage vMotion has changed for a third time in as many releases, this time using “Mirror Mode” to mirror writes to in-progress vMotions. It also now supports migration of vSphere snapshots and Linked Clones. This can be offloaded for VAAI block, but not NFS.

vSphere Replication

New in vCenter Site Recovery Manager 5.0 is software-based replication. Although not technically a vSphere 5 feature, this is a major new storage feature in the VMware world. It allows any-to-any software-based storage replication for disaster recovery.

Stephen’s Stance

Once again, VMware added a ton of new storage enhancements to vSphere. With storage rapidly becoming the limiting factor in scalability and performance of virtual machine environments, this is no surprise. Also not surprising is the fact that major features like Policy-Driven Storage and Storage DRS (along with SIOC) are exclusive to “Enterprise Plus” licenses. I can’t blame VMware for making a buck, but it would be nice if more capabilities were available to the small shops!

I’ll be writing on all these features in detail shortly. Watch this space!