Error after vSphere update

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Error after vSphere update

Veeam Logoby pizang » Sat Aug 15, 2009 8:17 pm

One of my backups stopped working after upgrading whole infrastructure to vSphere. I received and error:

Retrieving file list
VCB error: Error: Other error encountered: Snapshot creation failed: File <unspecified filename> is larger than the maximum size supported by datastore '<unspecified datastore> An error occurred, cleaning up...

This is a one machine backup. This machine has 2 disk
system disk of size 10 GB - 175 GB of free space
data disk of 500GB - 200MB of free space

Data disk is on VMFS volume that has maximum data size of 512GB (block size of 2MB).I guess this is a problem. But why? Snapshot is made on system disk's VMFS. Is it somehow "added" to base disk and than it exceeds 512 GB limit?
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Re: Error after vSphere update

Veeam Logoby Vitaliy S. » Sat Aug 15, 2009 9:04 pm

Hello Miroslaw,

Are you able to do the snapshot manually using vSphere client? Is it a thin provisioned disk (10 GB and free 175 GB of free space)?
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Re: Error after vSphere update

Veeam Logoby pizang » Sun Aug 16, 2009 6:44 am

Hello Vitaliy,

No I am not able to do a manual snapshot. vSphere Client shows exactly the same error.
This is thick drive, all my drives are thick.

I thought that free space on VMFS volume where VM resides is enough to make a snapshot. Should I create a new VMFS with larger block?
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Re: Error after vSphere update

Veeam Logoby Vitaliy S. » Sun Aug 16, 2009 7:47 am

Miroslaw,

Yes, everything points that 2MB block size is not enough to make a snapshot, you can format new VMFS volume with larger block size and then move VMs causing issue there, I believe it'll resolve your issue.

Thanks.
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Re: Error after vSphere update

Veeam Logoby drbarker » Sun Aug 16, 2009 10:12 am

vSphere changed the limits in a few places... Max datastore (& file?) sizes all shrunk by 512 bytes.

See (under 'storage maximums'):
http://www.vmware.com/pdf/vsphere4/r40/ ... ig_max.pdf
http://www.vmware.com/pdf/vi3_35/esx_3/ ... ig_max.pdf

Apparently, ESX 3.x had the same limitation with the last 512 bytes - it just never bothered inforcing it.

As vsafarov says, to get around it, create a new VMFS store with a 2Mb block size. You won't be able to do an online storage motion, so you'll have to shut down the guest, then move from the old datastore to the new one.
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Re: Error after vSphere update

Veeam Logoby pizang » Tue Aug 18, 2009 9:38 am

I have created a new LUN the same size as the old one - 512GB. I have created a new VMFS volume with 4MB block size (so it can hold files as big as 1TB). I have powered down my VM and moved disk 2 (data disk) to new VMFS.

To my surprise I received exactly the same error:
File <unspecified filename> is larger than the maximum size
supported by datastore '<unspecified datastore>


Is, by any means, block size of configuration file's partition involved? What I mean is that VM configuration file and VM system disk is stored on partition with block size of 1MB. I have checked and only two VM has problem with snapshot and both of them (and only them) have virtual disks larger than 256GB. As snapshot file is stored on disk where configuration file is located maybe it can cause a problem? Maybe system is checking block size of snapshot partition?

Second idea is lack of space on data disk. There are only 170MB left as I maximized virtual disk size. But it should not be a problem as snapshot file is on different disk. I have another VM with data disk of 200GB, no significant space left and snapshot is working.
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Re: Error after vSphere update

Veeam Logoby pizang » Wed Aug 19, 2009 9:06 pm

I have resolved this. I have moved VM config file to VMFS with 8MB block. Snapshot was created without any error. So ESXi 4 changed the rules. It is checking whether snapshot destinantion VMFS has block size equal or grater than disk that you are snapshotting.
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Datastore Block Size Requirements

Veeam Logoby DocMac100 » Wed Mar 24, 2010 9:16 pm

I'm trying to backup a guest that is on a datastore with a block size of 1mb, which is the block size of all of my datastores, and I'm getting "Snapshot failed: File is larger than the maximum size supported by the datastore".

I understand that a block size of 1mb limits my datastore size to 256gb, but why would the snapshot process be creating a file larger than 256gb? Could it be that the datastore itself is too small?
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Re: Datastore Block Size Requirements

Veeam Logoby DocMac100 » Wed Mar 24, 2010 9:22 pm

The failure depends on the size of the virtual disk. All virtual machines having disks with a maximum supported size by VMFS may experience this error.

For example, a virtual machine with disk sized 256 GB stored on VMFS with 1MB block size fails to snapshot because of the additional overhead required for the delta files. Though the maximum file size for a 1MB block size is 256GB - 512, creating a vmfsSparse (delta) disk requires additional overhead space about 2GB. The resulting delta has potential to grow beyond the file system limit.

To resolve this issue, move the virtual machine to a VMFS volume with 2MB block size.

Overhead for the snapshot is roughly about 2GB for a disk size of 256GB. If snapshots are to be used, consider the overhead while deciding the size of the disks.
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Re: Datastore Block Size Requirements

Veeam Logoby Vitaliy S. » Wed Mar 24, 2010 10:12 pm

Hello Doc,

Thank you for answering your own question :wink: I'm sure it will be helpful for other users also!
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Re: Datastore Block Size Requirements

Veeam Logoby Gostev » Wed Mar 24, 2010 10:14 pm

Also here's the existing thread with additional details about this issue:
http://www.veeam.com/forums/viewtopic.php?f=2&t=1615&hilit=maximum+size+supported+by+datastore
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Re: Error after vSphere update

Veeam Logoby lewislampkin » Tue Oct 12, 2010 6:26 pm

Hi, I'm new here. But, I am getting the same error message as the original poster.

His problem was something with block size, so I'll share the details about the particular VM and datastores giving an error (others are backing up just fine so far).

All thin provisioned (if that matters)
VM disk1 (System): 80 GB datastore: 183 GB, 1 MB block size
VM disk 2 (Data): 512 GB datastore: 1.82 TB, 8 MB block size
VM disk 3 (Data): 512 GB datastore: same as VM disk 2
VM disk 4 (Data): 512 GB datastore: same as VM disk 2

Target datastore: 1.82 TB, 8 MB block size

OK, I resolved my own issue, before I could complete this post, but including it for completeness ...

The issue is that there is an option to "check space" when you are setting up the job properties. Had I done this in the first place, I would have prevented the error. Irregardless, I went into the job properties, checked the space, and saw this error. The error said I didn't have enough space to do this job, within the retention policy. In this case, I modified the job, and took it from the default of 14, back to 13. (Not a big deal, as it is only a test server, in the first place.)

OK, problem solved, and the job now runs just fine.

Can now use this as a "planning tool" to calculate space required, based on the number of backups I want to retain.

Thanks for making such an easy to use product!
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Re: Error after vSphere update

Veeam Logoby lewislampkin » Wed Oct 13, 2010 11:32 am

OK, problem not sorted. I'm going to break out this server, and set up a job for each drive, and see if a particular drive fails the job.

EDIT:
Individually, each drive still fails.

Not sure what the problem is ... anything about my setup suspicious?

If it would tell me where it is placing "unspecified filename" and what was the "unspecified datastore" I might know better, but I posted my setup, and not sure what I'm missing.
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Re: Error after vSphere update

Veeam Logoby Vitaliy S. » Wed Oct 13, 2010 12:19 pm

Lewis,

It won't make much difference if you brake the job to backup particular virtual disks separately. The reason why you see the error is that a snapshot is created on the same datastore where main VM configuration files are located (in your case it 1 MB datastore, which doesn't meet the requirements). As you probably know when snapshot is taken it affects all disks attached to the VM and the only way to exclude the disk from snapshotting is to make it independent, thus meaning you won't be able to backup it either. To resolve the issue you need to reformat the datastore (with VM disk1 on) with a larger VMFS block size.

Thank you!
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Re: Error after vSphere update

Veeam Logoby lewislampkin » Wed Oct 13, 2010 1:42 pm

Vitaliy S. wrote:Lewis,

It won't make much difference if you brake the job to backup particular virtual disks separately. The reason why you see the error is that a snapshot is created on the same datastore where main VM configuration files are located (in your case it 1 MB datastore, which doesn't meet the requirements). As you probably know when snapshot is taken it affects all disks attached to the VM and the only way to exclude the disk from snapshotting is to make it independent, thus meaning you won't be able to backup it either. To resolve the issue you need to reformat the datastore (with VM disk1 on) with a larger VMFS block size.

Thank you!


Vitaly,

I did not realize this about the snapshots, and that provides an important warning to me, with regards to planning my storage layout. I am probably at novice level, with regards to this stuff, just another hat to put on at the office, you know?

Thanks for your help, it makes perfect sense now.
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