A disaster is a catastrophic interruption of business processing that destroys the Tivoli Storage Manager server, clients, or both.
Tivoli Storage Manager Server
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Restore files &
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There are many levels to consider for a disaster. You can imagine a situation where a user deletes a file and requests a restore (to them it might indeed be ’a disaster’). A complete directory might be lost; an application server might be infected with a virus, causing an unknown extent of damage; a disk might be lost on a fileserver; or a full datacenter building with many machines might be completely destroyed. Depending on the business requirement, you will need to answer bigger questions, like what kind of recovery do you need and how long do you have to provide it. Figure 80 shows some of the well-known techniques that you can apply to your environment to safeguard from data loss.
Figure 80. Disaster recovery techniques
Tivoli Storage Manager and Tivoli Disaster Recovery Manager can provide assistance to you in the following situations:
• Reconstruction: A reconstruction means that you want to rebuild your previous working environment at the same place and to the same state as it was before. This also means that you do not have all required machines available to start and therefore, you will need to contact local dealers to provide you all the hardware and software needed. Assuming that you have saved your vital data to an alternate offsite location, Tivoli Disaster Recovery Manager will help you rebuild your Tivoli Storage Manager server, so that you can then restore the client nodes up to the last known saved position.
• Cold Site: In this scenario, you may have all spare hardware and software available, but not properly configured or ready for usage. Some preliminary steps are still required to prepare the infrastructure. In this case, Tivoli Storage Manager will have to be installed with all additional required software. You then restore your latest database backup, and restore the storage pools, using the DRM recovery plan. You can then restore the clients, starting with the most critical.
• Hot Site: Generally, a hot site will have all the infrastructure hardware and software in place, so that you need to focus on business information
60%
Mirror... Vaulting... Hot Site... Cold Site... Reconstruction Recovery window is the time from disaster striking until you are back in full production.
Recovery Window x Customers
Techniques Implemented
recovery, rather than infrastructure. However, you will still need to bring your data to the hot site location. Assuming that your hot site has all basic software installed (Tivoli Storage Manager included), you will need to recover your backup server and application data by using the recovery plan file and database backups.
• Vaulting: This provides you all hardware, software and data requirements for recovery. In this case, you need to concentrate solely on business recovery, since all data is already available to you. Tivoli Disaster Recovery Manager offers a complete set of tape state controls to make tape vaulting easy and precise. All offsite tapes can have one of the following stages:
Mountable, NotMountable, Courier, CourierRetrieve, Vault, VaultRetrieve, OnsiteRetrieve. This governs how the recovery will be affected if, for example, the volumes are in transit to offsite (courier) and did not reach the offsite location (vault).
• Mirror: A mirror site normally replicates all required data simultaneously, so that whenever you have a failure in the primary image, the copy (or copies) can be used without interruption of business activity. This is the only situation that you may not need Tivoli Disaster Recovery Manager at all, since you already have an alternate, secure and up-to-date condition for your data. However, you could still consider using Tivoli Disaster Recovery Manager to control other machines that are not being mirrored to this site.
Backup operations can guarantee the first level of protection, which is when main data is somehow lost, inconsistent or damaged. Unfortunately, if your backup tapes are located in the same place as your production data, then you risk losing your only safeguard. Figure 81 shows a typical situation where offsite data storage is used. The latest file changes are sent to the offsite location, so that you can use it together with previous data sent.
Figure 81. Sending data to offsite location
Backup data is located offsite to protect it from damage. Data does not need to be lost or destroyed in order to be unavailable. In recent disasters, data
inaccessibility appeared to be caused as much by condemned buildings and evacuations as by destruction. Companies need to plan for the physical accessibility of data, not just the survival of data.
In today’s world, however, it all depends on who you are, where you are, and what you were doing. Today’s disaster can be characterized by the business you are in (for example, banking, e-commerce, distribution, or manufacturing). In banking or e-commerce, time is very important. One hour of
downtime—regardless of how it is caused—can mean business loss amounting to millions of dollars. In the e-commerce world, if you cannot satisfy your customer’s requests, they may go to a competitor and never return to your site. The potential losses may not be as large in manufacturing or distribution. But whatever the business is, the longer the downtime, the greater the loss that the business incurs and the greater the risk that the business may never recover from the loss.
Disaster recovery management is accomplished with Tivoli Storage Manager by a combination of:
• Backing up client data to the Tivoli Storage Manager server
• Backing up the server database to removable media and storing the media offsite
• Backing up the primary storage pools and storing the media offsite
• Using the disaster recovery plan file to assist with the Tivoli Storage Manager server recovery
• Optionally using LAN-free recovery options, such as backupsets where available and appropriate to improve recovery
Tivoli Storage Manager
• Optionally using virtual volumes to save data, recovery plan file and database information electronically to an alternate Tivoli Storage Manager server