This topic describes considerations for determining what file-placement
policies you want to implement.
The SAN File System uses policy rules to determine how files are placed
in the user storage pools. Each rule in a policy specifies the fileset to
which the rule applies and the storage pool in which user data will be stored.
In addition, it includes conditions for storing the files. These conditions
are typically based on file attributes, such as file name, owner, group ID
of owner, or the system creating the file.
Although defining rules for file placement based on creation time, user
ID, or group is supported, use these clauses with care. When files are restored
from a backup or migrated, these attributes are changed. For example, the
following changes occur when files are restored from backup:
- Creation time is set to the time the files were restored.
- The user and group are set to the user and group of the application used
to restore the files.
You can define multiple policies for the SAN File System. However, only
one policy can be active as any one time.
Important: In a
non-uniform zone configuration, the clients can access only the storage pools
in their zone. You must verify which filesets each client uses, and ensure
that the policy rules use only storage pools that the clients can access.