Gauri -
What is so difficultl to underwstand about
"Compression was working before SP4a but is not working afterward"
It doesn't matter what kind of data is being backed up Jobs that did compress at reasonable rates before SP4a no nolonger do ANY compression after.
I'd have to hunt up the thread, but one fellow ran a SCSI trace and can see the command to turn compression off transmitted to the drive.
Once again, just like when SP4 was originally released, Veritas/Symantec have a problem, documented by many customers and refuse to accept that they indeed are responsible