Cannot add new rollback snapshot

SFS rollback uses to manage volume-level snapshot, sometimes fails to add any new rollback snapshot,

sfs> storage rollback create space-optimized data-fs1-snap data-fs1 data-cache
SFS rollback ERROR V-288-1883 fsck failed for data-fs1-snap.
sfs> storage rollback cache list
CACHE NAME TOTAL(Mb) USED(Mb) (%) AVAIL(Mb) (%) SDCNT
data-cache 204800 204800 (100) 0 (0) 13

sfs> storage rollback list
 NAME TYPE FILESYSTEM SNAPDATE
 data-data1-snap spaceopt data-data1 2012/08/15 14:16
 

You need to delete old rollback snapshot to release cache space,

sfs> storage rollback destroy data-data1-snap data-data1

Try again to add new rollback snapshot,

sfs> storage rollback create space-optimized data-fs1-snap data-fs1 data-cache
100% [#] Create rollback