We have an EMC Isilon configured with a Backup Accelerator and cannot perform differential backups using TSM 5.5.
There are several virtual filespaces defined on TSM, and run backups on a weekly basis.
Numerous FULL backups have been executed across all filespaces, even test filespaces with less that 10MB of data, all complete Successfully according to the TSM actlog.
However the backups always default to FULL even though mode=diff is defined.
The command we use is -
backup node isilon /backupfolder toc=yes wait=yes mode=differential
This occurs on every filespace. I can scroll through the TOC for each filespace, and can restore the entire filespace to an alternate location without problem, so the backups are definitely working, however no differentials work.