Backup to SmartDisk fails with "Fatal error writing backed up data" (4038655)

In the binary log we see “Failed to get available space when writing stream data”  and in the SmartDisk trace we see “Task has failed as the attempt to reserve space in the storage file failed”

The SmartDisk is configured to with deduplication disabled and customer has enabled compression on stage and store volume. I this case only stage volumes will be used  for storing data.

From binary log:

Error      2015/11/19 23:01:02       67           Data Plugin         DPEX01 Stream has gone down

SevereError         2015/11/19 23:01:02       67           Data Plugin         DPEX01 Fatal error writing backed up data: '(null)'

SevereError         2015/11/19 23:01:02       67           Data Plugin         DPEX01 Failed while backing up items

NET     :36272   69   10053 230102 Fatal error during TCP send: Connection aborted due to timeout or other failure (10053)

PLGLIB  :36272 1591       0 230102 Failed to send 32768 bytes to RAS DAV connection

PLGLIB  :36272   83       0 230102 Failed to dispatch data

PLGLIB  :36272   93       0 230102 Backup Stream Down

NVFSWIN :36272  415       0 230102 Failed to get available space when writing stream data

NVFSWIN :36272 1100       0 230102 Fatal error writing stream data

NVFSWIN :36272 1094       0 230102 Fatal error backing up streams of 'C:\NvbuShadowCopy_18980\inetpub\logs\LogFiles\W3SVC1\u_ex151118.log'

Storageservice traces show below error in trace:

0 FILESYS ??? 14 155146653052 Failed to set file size to 22548578304 : 665:The requested operation could not be completed due to a file system limitation

0 DAVLAY ??? 90 155146653052 Failed to set file size when allocating more space in '\\?\G:\smartdisk\stage\diskmanager\data\670500004dbb4b56a6bc7ecd081e000048320100'

0 DAVLAY ??? 127 155146653052 Task has failed as the attempt to reserve space in the storage file failed

Compression on the volume cause fragmentation of the volume which resulted in the errors we see.

Remove compression from all SmartDisk volumes. 

Remove old backups if possible from NetVault using explore storage. Some backups may not be possible to remove as they may not be a second copy of the data on tape or the back pretension policy will not allow the removal of these backup. 

Note: compressed volumes are not supposed to be used for SmartDisk storage and a test restore would be advised to verify that this data is restorable.

Stop SmartDisk services run defragmentation on the volumes

On defragmentation completion start SmartDisk.