HP snapshot backups using DRM
Data Replication Manager(DRM) from HP
Snapshot creates a temporary unit to store original data that has been overwritten
on the source. It does not copy all the data, unchanged data is read
from the source. Snapshot requires that both controllers have 512MB
of mirrored cache. The resultant Snapshot Unit is read only. Up to 4
snapshot units can be created per Source Unit.
The snapshot command is
ADD SNAPSHOT-UNITS snapshot-unit storageset source-unit
- Source Unit is the unit name where the original data exists, and must be less than 512GB
- Snapshot Unit is a user supplied name for the copy data
- Storageset is the unassigned capacity that will be used for the Snapshot Unit. The capacity of the storageset must be equal to, or greater than the capacity of the Source Unit
The point-in-time is the instant the command is entered.
The clone utility creates a complete copy of the data internally, and can copy at up to 60GB/hour if the IO load on the box is not excessive. There is no limit, beyond device capacity, to the number of clones that can be created. Once the clone command completes, it splits the two copies so they can be accessed independently. The copy point-in-time is the end of the clone process, not the time the command was issued.
Cloning is an interactive process, a typical dialogue, with user input in bold type would be
Run Clone Clone local program invoked Units available for cloning: 34 Enter unit to clone ?” 34 clone will create a new unit which is a copy of unit 34 enter the unit number which you want assigned to the new unit ? 42 The new unit will be added with one of the following methods: 1. Clone will pause after all members have been copied. The user must then press return to cause the new unit to be added. 2. After all members have been copied, the unit will be added automatically Under which above method should the new unit be added  ? 1 Devices available for clone targets Disk20300 (size=832317) Disk20500 (size=832317) Disk30300 (size=832317) Use available device disk20300(size=832317) for member Disk10200(size=832317) (Y,N) [Y] ? Y Mirror disk10200 C-MA SET C-MA NOPOLICY SET C-MA MEMBERS=2 SET C-MA REPLACE=DISK20300 Devices available for clone targets Disk20500 (size=832317) Disk30300 (size=832317) Use available device disk10300(size=832317)for member disk(size=832317)(Y,N)[Y] ? Y Mirror disk100000 C-MB SET C-MB NOPOLICY SET C-MB MEMBERS=2 SET C-MB REPLACE=DISK10300 Copy in progress for each new member, please be patient.. . . copy from disk 10200 to disk20300 is 100% complete copy from disk 10000 to disk10300 is 100% complete press return when you want the new unit to be created .. some mirrorset messages .. D44 has been created, it is a clone of D32 Clone- normal termination
Snapclone is only available on the newer EVA subsystem. The snap data is available almost immediately even while clone is being built. The data copy starts out as a Snapshot and becomes a Clone once the data copy is complete.