Data Centers

vSphere 5 introduces Storage DRS

VMware vSphere's new ground-breaking feature is Storage DRS, which extends the Distributed Resource Scheduler to the storage stack. Read about some of the automation interface's features.

Storage DRS has been previewed at VMworld and other events since around 2009, and it will finally be public in VMware vSphere 5. Storage DRS extends the Distributed Resource Scheduler (DRS) to the storage stack and provides three main categories of functionality with vSphere 5:

  • Initial placement of virtual machines and their associated disks (VMDK files) based on space availability and I/O capacity.
  • Load management among datastores in a datastore cluster leveraging Storage vMotion based on space availability.
  • Load management with Storage vMotion based on datastore latency (in milliseconds checked every 8 hours by default).
The key new piece of the pie here is the datastore cluster. It's a pool, if you will, of individual VMFS-5 volumes (NFS is also supported) that are logically presented as a cluster. This is shown in Figure A (note that uniform underlying volume size is not required). Figure A

It is important to remember that each of these individual datastores are still visible within vSphere. Further, the configuration options within Storage DRS focus on the capacity and latency of the datastores to best meet the configuration. What I like about Storage DRS in vSphere 5 is that it configured by the latency and free space metrics on a sliding scale of priority. The pre-release version of this screen is shown in Figure B. Figure B

Click the image to enlarge.

With this configuration, virtual machines can undergo a Storage vMotion task to a datastore that performs better in terms of latency. Further, this can be automated with this configuration. A good design point for this configuration is that we would put datastores of the same storage tier in this datastore cluster. Specifically, we don't want to mix SSD datastores with SATA datastores or even the same drive types of different speeds.

Does Storage DRS interest you? How would you utilize it with a datastore cluster? Let us know in the discussion.

Also read: vSphere 5 introduces VMFS 5

About

Rick Vanover is a software strategy specialist for Veeam Software, based in Columbus, Ohio. Rick has years of IT experience and focuses on virtualization, Windows-based server administration, and system hardware.

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