Requirements for the cache partition
Note the following requirements:
Must reside on the same host as the raw partitions containing the source data to back up.
Cannot be the raw partition being backed up.
Cannot be a mounted file system. Any data that is configured on this device may be overwritten by the copy-on-write process.
On Solaris, the same cache partition may be used simultaneously by multiple backups (two policies can use the same cache partition at the same time). On HP, multiple backups cannot use the same cache partition simultaneously. If multiple policies list the same cache partition on HP systems, backups naming those policies must run at different times to prevent a failure.
The cache partition must have enough space to hold all the writes to the source data that may occur during the backup. Backups during off-peak hours normally require a smaller cache than those during peak activity.