Dell PowerVault DP600 - Manual (Page 37)

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Recovery Goals for Disk-Based Protection
Although all members of a protection group share the same synchronization frequency, the
synchronization process and the resulting recovery point schedule differ based on the type of
data being protected. For more information, see How DPM Works .
Synchronization and Recovery Points for Files
For a file volume or share, the protection agent on the protected computer tracks changed blocks
in the change journal that is part of the operating system. During synchronization, these changes
are transferred to the DPM server and then applied to the replica to synchronize the replica with
the data source.
You can select a synchronization frequency interval of anywhere from 15 minutes to 24 hours.
The default is 15 minutes. You can also select to synchronize only before a recovery point is
created.
Recovery points, which are shadow copies of the replica for file data, are created from the
synchronized replica on a configurable schedule. Each file synchronization does not result in a
recovery point unless you synchronize only before each recovery point; however, you can
manually create a recovery point from the most recent file synchronization.
For example, a volume is synchronized hourly and a recovery point for the volume is created at
8:00 A.M., 12:00 P.M., and 6 P.M. A user makes changes to a file on the volume at 1:30 P.M.;
however, when another user makes changes an hour later, the file is inadvertently corrupted, and
you are asked to recover the file with the first user's changes. Because the changes at 1:30 P.M.
were made after the most recent recovery point was created at 12:00 P.M., you cannot recover
the file from the most recent recovery point. However, you can manually create a recovery point
from the appropriate synchronization of that replica and then recover the file from that new
recovery point.
The default schedule creates recovery points at 8:00 A.M., 12:00 P.M., and 6:00 P.M. daily. You
can modify both the times and the specific days. You cannot specify different times for different
days. For example, you can schedule recovery points for 2:00 A.M. and 2:00 P.M. on weekdays
only; however, you cannot schedule recovery points for 2:00 A.M. on weekdays and at
12:00 P.M. on weekends.
Retention Range for Files
Retention range is the duration of time for which the data should be available for recovery. When
the retention range for a recovery point expires, the recovery point is deleted.
You can select a retention range between 1 and 448 days for short-term disk-based protection,
up to 12 weeks for short-term tape-based protection, and up to 99 years for long-term tape-based
protection. DPM can store a maximum of 64 recovery points for each file member of a protection
group.