vSphere Storage Appliance

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  • 1.  VM with large storage requirement

    Posted Aug 27, 2011 08:03 PM

    Hello all,

    I have a requirement to build a vm with 12TB of storage.  The vm is going to be a Windows 2008 R2 file share server with 7TB of actual data to start off with. (The shares are being migrated from an old physical system.)  There are approx 100-150 users for this data.  The data is not very volatile.

    I'm looking for suggestions on how to setup the storage for the vm.

    I'd like to take advantage of thin provisioning, keep datastores from being constantly above alerting thresholds (85%), and not waste a lot of space.

    One thought was to create 6 2TB RDM's.  However, that would waste about 5TB of space not currently being used.  The data will grow over time, but I'd rather not allocate it now if I didn't have to.   (Windows will need to report 12TB upfront.)

    Another thought was to create 8 2TB datastores and allocate approx. 1.6 TB (80% of the datastore) thin-provisioned vmdk's from each datastore to the vm.  The thin provisioning might help with unused space, but there would still be 400GB essentially unused on each datastore.

    I'm not sure if there may be other considerations as well.

    Any thoughts or ideas would be appreciated.

    Thank you...

  • 2.  RE: VM with large storage requirement

    Posted Aug 27, 2011 08:20 PM

    This sounds as if you will have to take a look at vSphere 5.0. With vSphere 5.0 you can create VMFS datastores of up to ~64TB (assuming your storage is able to present LUNs > 2TB). You could create one datastore with 6 thin provisioned virtual disks, each 2TB minus 512 Bytes (this is still the limit for files on VMFS). With this approach you can start with a small datastore and increase it on the fly as needed.


  • 3.  RE: VM with large storage requirement

    Posted Aug 27, 2011 08:22 PM

    ... btw. vSphere 5.0 will also allow RDM's in passthrough mode (physical mode) with up to ~64TB.


  • 4.  RE: VM with large storage requirement

    Posted Aug 28, 2011 09:27 PM

    Have you thought about having Windows concatinate the disks?    I'm most definitely not a Windows guy but you should be able to present 6 2TB disks and create a dynamic volume set of 12TB.  You can start with 8TB and then grow the volume set in 2TB increments (although each member of a volume set doesn't have to be the same size).  Unless the limit has changed recently, you can have 32 members of a volume set.

    BTW, if that single large system file fails or needs a chkdsk, you're in for a world of hurt but I assume you know that already.

  • 5.  RE: VM with large storage requirement

    Posted Aug 31, 2011 06:27 PM

    Thanks everyone for your replies on this.  I did forget to mention that were using vSphere 4.1 currently, so that's the environment where this will need to be built.  ESX 5 does look like it would be a much better fit, but unfortunately it won't be in place before this vm will need to be built.

    Instead of building out this huge drive, I may go back and see how the data can be organized/compartmentalized better, still providing the overall amount of space, but broken up in more manageable (and expandable) chunks.

    Again, I appreciate the help and if anyone else has some thoughts, that would be appreciated as well.

  • 6.  RE: VM with large storage requirement

    Posted Aug 31, 2011 07:10 PM

    If your SAN (assuming you are using one) offers CIFS then why not use it directly. You can also use a NAS along with Windows DFS to restructure a file system from multiple VMDKs.