By default, a Standard storage policy directs subclient backup/archive data from
all types of backups/archive operations, including full and non-full (incremental
and differential) backups (as well as new index and appended indexes for archiving
operations) to the same storage policy. This may not always be time and cost efficient
if your storage policy is using the same resources.
For iDataAgents, to reduce your backup
window and utilize storage resources effectively, you can define a storage policy
for full backups and another storage policy, called an Incremental Storage Policy,
for non-full backups.
In such a configuration, it is recommended that the full storage policy use tape
media, and the incremental storage policy use disk media to effectively utilize
the available resources.
In the following example, Subclient A is backed up using a storage policy which
has the incremental storage policy option enabled. Hence, the full backup uses a
storage policy that backs up to a tape library. The incremental and differential
backups use a storage policy that backs up to disk media.
To configure your subclients to use this feature, the incremental storage
policy must be enabled in the Storage Policy Properties dialog box.
In the sample image, SP_Mag_Library2_2
is enabled as an Incremental Storage Policy for storage policy
SP_Tape_Library1_1.
Multiple storage policies can enable the same storage policy as its Incremental
Storage Policy.
However, within the storage policy that is enabled as an Incremental
Storage Policy, you will not be able to enable the Incremental Storage Policy
option, as it is not available.
In the sample image that follows, the Incremental Storage Policy option
is not available in SP_Mag_Library2_2, as
it is already enabled as an Incremental Storage
Policy for SP_Tape_Library1_1.
For this reason, the list of incremental
storage policies displayed in this dialog box will include only those storage
policies that do not have an Incremental Storage Policy enabled.
In the sample image that follows, the list of incremental storage policies
in SP_Mag_Library3_3 does not include
SP_Tape_Library1_1, as
SP_Tape_Library1_1 has an Incremental Storage
Policy enabled.
Once this is done, your subclients that are configured to use the storage
policy that has the incremental storage policy option enabled will use different
storage policies for full and non-full backups. This information can be
viewed from the Storage Device tab of the
Subclient Properties dialog box.
Note
that the name of the Incremental Storage Policy is also displayed.
If you want to perform a synthetic full backup using an alternate MediaAgent (one other than
the MediaAgent used for the Primary backup), you must configure an Incremental Storage Policy.
You cannot enable a storage policy as an incremental storage policy if that
storage policy already has an incremental storage policy enabled.
The incremental storage policy option is available for a Standard storage policy.
If you are using a different MediaAgent for an incremental storage policy
than the MediaAgent used for a full storage policy, one of the following
conditions must be met:
The primary copies of both this storage policy and the selected
incremental storage policy use a
shared index
cache.
The primary copies of both this storage policy and the selected incremental storage policy are set to use preferred data paths.
If it is a case of failover/round robin, the primary copies of both this storage policy and the selected incremental storage policy
must have the same data paths.
An incremental storage policy must be de-associated from a storage policy
before that storage policy can be deleted.
If an incremental storage policy is de-associated from a storage policy,
the most recent incremental backup may be pruned before the next full backup
occurs.