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38574
May 16th, 2011 09:00
Reformatting a volume with 4mb block
I have two 1TB volumes on my san. Last friday I was tring to move a fairly large vm to it. And I got this error:
"vmdk is larger than the maximum size supported by datastore "
The volume's current block size is 1MB and it appears I need to reformat it using a 4mb blokc size.
I don't see any option to reformat it under the Volume Manager, only to delete it.
How do i reformat it using a 4mb block size?
Thanks,
Cheto06
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mfkelly_tx
31 Posts
1
May 16th, 2011 09:00
You must delete it from vSphere, then "Add Storage" and choose the appropriate block size. Be sure it does not have any VMs on it before doing this, it is destructive.
cheto06
9 Posts
0
May 16th, 2011 09:00
This did it!!
Thanks a lot- now I'll need to wait until Friday to try again,
JOHNADCO
2 Intern
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847 Posts
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May 19th, 2011 09:00
Just an additional note? We always go one block size larger than needed. This assures no future issues with this as your enterprise thus this VM grows.
Dev Mgr
6 Operator
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9.3K Posts
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May 19th, 2011 11:00
I would take it one step further; I usually recommend to just use 8MB blocks for everything as the 'wasted space' is so minimal with current disk sizes (~15 files per VM and if you average it out you'd be wasting 4MB per file, times the 15 files means you're 'wasting' 60MB is VMFS disk space per VM -> nobody would miss that).
Picking a smaller block size and later realizing you need a larger one could take downtime (if you don't have storage vMotion).
JOHNADCO
2 Intern
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847 Posts
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May 19th, 2011 13:00
Smaller volumes with extents on VMware faster? I don't think so.
Smaller volumes without extents where the application(s) can add and manage it's own data? I tend to agree.
Problem is? Nearly every store gets to 2TB eventually as was the point of my post.
Extents are scary. I hate the 2TB limit in VMware with a passion.
JOHNADCO
2 Intern
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847 Posts
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May 19th, 2011 16:00
That would be nice. That limitation is about the only thing I don't like about VMware.
If another department allocates the storage? Try getting them to give you more smaller luns? Fat chance... In that case? always request them a 2TB - 512 bytes or whatever it is max in Vmware.
Dev Mgr
6 Operator
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9.3K Posts
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May 19th, 2011 22:00
With older SANs (or older firmware, depending on the SAN), this was definitely the case due to the disk (datastore) locking that would occur when a VM wanted to write to it's disk. But with some of the current SANs and the firnware, the locking is handled by the SAN and done on a block level. This should (I haven't personally compared it) mean that there is no more performance difference between using multiple smaller volumes or a few larger volumes (up to 2TB of course).
jpiscaer
1 Message
1
July 6th, 2011 11:00
This error is due to a too restrictive block size on your VMware VMFS. This is the filesystem that sits on top of the EqualLogic volume. There's nothing to modify on the EqualLogic level. If you want files up to 2TB (8MB blocksize), you'll need to reformat te volume. This is done in the vSphere Client.
Please be aware of the fact that reformatting removes *all* VMs. You'll need to Storage vMotion all VMs away from the VMFS datastore you are going to format. After format, you can move them back.