Disaster recovery Management
Disaster recovery is the process of restoring data in case if any disaster happens.
Various stages of DRM-:
Mountable
NotMountable
Courier
Vault
VaultRetrieve
CourierRetrieve
OnsiteRetrieve
On-site → off-site
Tapes move through the following states during their journey off-site:
Mountable
NotMountable
Courier
Vault
Mountable: Newly created copy storage pool and database backup tapes are in a mountable state while they are online in the tape library (i.e. they can be mounted in a tape drive). A disaster would destroy these tapes as they have not yet been taken safely off-site. DRM knows that these tapes are not part of the guaranteed recovery set when creating its recovery plan. The next step for these tapes is to remove them from the tape library using DRM commands.
NotMountable: The media are removed from the library but are still on-site, that is, they cannot be mounted. The media are probably in the datacenter itself, waiting to be taken off-site. The actual physical location is not important for Tivoli Storage Manager. What is important is that volumes are still on-site and it is assumed that they would also be destroyed in a disaster. The NotMountable state only changes when the media are taken off-site, usually by courier pickup. You use a DRM command to change the state of the eligible media.
Courier: An intermediate state in which you consider the media as being in transit to the vault. You consider the physical transition from your on-site location to the vault as a potential risk. For example, suppose that you have a service agreement with an external company to transport your DR media. Although you rely on the staff and the company to safely move the media, there is a small possibility that some of the media could be lost or damaged during transportation. The Courier state is a critical step for media movement (and proper disaster recovery) because you cannot assume that media in the Courier state has safely reached its destination. DRM takes the Courier state into account if you create a recovery plan file just after changing the tape state to Courier. Once you are sure that all tapes have reached their destination, it is safe to change to the next and final state.
Vault: Once you have acknowledgement that the media have been safely received at the vault, you can change them to the Vault state. Vault is the final state in moving a tape from an on-site location to off-site. Data on the media will not begin to expire until the media reach the Vault state.
Once the media are off-site, they stay there until they are eventually reclaimed (or are required for an actual recovery). When they are empty, they are then ready to begin the journey home. DRM query commands show which volumes can be retrieved, so you can issue a list to your vault administrator.
Off-site → on-site
Tapes move through the following states during their journey back on-site:
VaultRetrieve
CourierRetrieve
OnsiteRetrieve.
VaultRetrieve: When all data on an off-site tape are no longer valid, the tape state is automatically changed to VaultRetrieve. That is, the tape is still at the vault, but available to be brought back on-site for usage. Both Tivoli Storage Manager database backups and copy storage pool tapes become
VaultRetrieve once expired or empty. You should send a list of VaultRetrieve tapes to your vault administrators, depending on the schedule of the courier, so they know which tapes to find and send back. Tapes that are in VaultRetrieve status are still part of the safe recovery set until they are physically removed from the vault.
CourierRetrieve: Change a tape to this state when you know that it has been taken from the vault and is in transit. Similar to the Courier state, CourierRetrieve tapes may or may not be preserved safely in the event of a disaster. Once the media are received on-site, they are ready for the final state.
OnsiteRetrieve: Once the volumes are back on-site, you move them to the OnsiteRetrieve state, which updates or removes them from the volume history, as follows:
– The volume history record of a database backup (snapshot, full or incremental) is deleted from the Tivoli Storage Manager database. The volume can be returned to a scratch pool.
– The volume record of a scratch copy storage pool volume is deleted from the Tivoli Storage Manager database. The volume can be returned to a scratch pool.
– The volume record of a private copy storage pool volume is not deleted and the access mode is set to READWRITE. The volume cannot be returned to a scratch pool.
*EOD
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