VERITAS Storage Foundation 4.1 Oracle Administrator's Guide
Storage Checkpoint Allocation Policies Prerelease 8 September 2005, 8:55am
168 VERITAS Storage Foundation for Oracle Administrator’s Guide
Storage Checkpoint Allocation Policies
VERITAS File System provides Multi-Volume File Systems (MVS) when used in conjunction with
the Volumes Set feature in VERITAS Volume Manager. A volume set is a container for multiple
different volumes. MVS enables creation of a single file system over multiple volumes, each
volume with properties of its own. This helps administrators specify which data goes on which
volume types. For more details about MVS, see VERITAS Volume Manager Administrator's Guide.
Setting up a storage configuration for MVS operations is a system administrator's responsibility
and requires superuser (root) privileges.
Multi-Volume File Systems provide, a database administrator, through the SFUA checkpoint
administration interface, the ability to create Storage Checkpoint Allocation Policies. A Storage
Checkpoint Allocation policy specifies a list of volumes and the order in which to attempt
allocations. Once defined, a database administrator can use these policies to:
◆ Control where the storage checkpoint should be created enabling separation of metadata and
data of a storage checkpoint to different volumes.
◆ Separate storage checkpoints so that data allocated to a storage checkpoint is isolated from the
primary file system. This helps control the space used by the checkpoint and prevents the
checkpoint from fragmenting the space in the primary fileset.
When policies are assigned to a storage checkpoint, the database administrator must specify the
mapping to both metadata and file data. If no policies are specified for the storage checkpoint, the
data is placed randomly within the primary file system. Data and metadata of storage checkpoints
can have different policies assigned to them or use the same policy to be applied to data and
metadata. Multiple checkpoints can be assigned the same checkpoint allocation policy. A partial
policy is also allowed; a partial policy means that the policy does not exist on all file systems used
by the database.
Once the policy is assigned to checkpoints, the allocation mechanism attempts to satisfy the request
from each device in the policy in the order the devices are defined. If the request cannot be satisfied
from any of the devices in the policy, the request will fail, even if other devices exist in the file
system which have space. Only those devices can provide allocation that are listed in the policy.
This implementation is the mechanism for preventing allocation requests from using space in other
devices which are not specified in the policy. It is recommended that you allocate sufficient space
for the volumes defined in the Storage Checkpoint policy or update the policy to include additional
volumes. This also helps in retaining the old Storage Checkpoints.
Once the assigned policy is deleted, the allocation for metadata and file data for subsequent
requests of storage checkpoint will return to the no policy assigned state.
Usage Notes
◆ Since the checkpoint policies feature is associated with MVS file system, it is available only on
file systems using disk layout Version 6.