Creating Snapshot on ESXi 5.1 fails

[dspeight]

Hi

Im having a problem creating a snapshot on a certain virtual machine on ESXi 5.1. It fails with the error "File is larger than maximum file size supported". Now I've read through some KB articles including "1012384".. but I still cant quite determine the cause for the error.

VM is a fileserver with multiple harddisks.

Disk1 40GB, Disk2 1,9TB, Disk3 1,5TB, Disk4 2TB

The machine files including all disks are on a single datastore.

Datastore: VMFS 5.58, Blocksize 1MB, Capacity 7,81TB, Used 5,45TB, Free 2,36TB

I've read an article that the 2TB - 512B is a correct maximum for a file in ESXi 5.1 but that a certain amount of space is required for the snapshot overhead. ~16GB for a 2TB Disk. Could the 4th Disk with the Size of 2TB be the problem?

Ive added a screenshot. Sorry, its in german.. but it basicly says that a file (unspecified filename) is larger than the datastore (unspecified datastore) max size.

Thanks

David

[vembutech1]

Please note that snapshot operations are not possible for VMDK file with size larger than 2 TB minus 512 B in  ESX 5.0 and 5.1 VMFS 5 file system is present which has fixed 1 MB block size.. We need to keep the VMDK size less than or equal to maximum supported size. Hence, make sure the particular VMDK have enough free space for creating snapshots for that VM.

[dspeight]

The VMDK in question is below the maximum size. From what I've read the maximum size is 2,181,972,430,848 bytes. However the VMDK is around 2,147,000,000,000 bytes.

I dont quite understand why the VMDK needs to have enough space for creating snapshots. Do you mean the datastore? The VMDK is configured for 2TB Thick Provisioned Storage. Arent the delta files used for the snapshots? I a bit confused how its all calculated and stored.

Thanks

David

[a_p_ · Accepted solution]

... a certain amount of space is required for the snapshot overhead. ~16GB for a 2TB Disk. Could the 4th Disk with the Size of 2TB be the problem?

That's likely the case. The maximum size of a snapshot .vmdk file is the virtual disk's provisioned size, plus overhead (metadata), which must not exceed 2,048GB minus 512 Bytes with ESXi versions prior to ESXi 5.5 (or VMFS3 datastores). In order to create a new snapshot, it actually doesn't really matter how much free disk space you have on the datatore (It's up to you to monitor the free space to avoid out-of-disk-space issues), ESXi only checks whether the maximum possible file size is supported on the datastore, to allow the snapshot to grow as required.

André

[dspeight]

Thanks André, that helped alot. Makes sense that the size doesnt actually change. Rather just a maximum size check.

I've reduced the 4th disk to around 2000GB in size and everything is working well.

David