Hi Lizette, There have been some great appends to this question. I also wanted to add my two cents...
When determining your backup strategy, you need to determine the desired RTO (Recover Time Objective), RPO (Recovery Point Objective) and BWO (Backup Window Object) for both physical loss (storage failure) and logical loss (data corruption) at an acceptable price point. This can be daunting. You'll find that this may require that multiple backup strategies be used for the various types of data in your environment. To protect against physical data loss (some type of storage failure, whether it is a result of a failure with the storage itself or an external cause such as power outage, natural disaster, etc), there are many types of mirroring solutions. These solutions create two or more copies of the data at different locations such that if the primary storage fails, processing can switch to the alternate location. To protect against logical data loss (some type of data corruption, whether it is caused by a software defect or human error), there needs to be point-in-time copies. Mirroring solutions do not provide any protection here because the logical corruption is just instantly mirrored to all locations of the data. There are many different types of PiT copy techniques. One of the important factors is to ensure that the data is quiesced so that it is a data consistent backup. Or, that the recovery technique is able to create a consistent recovery from a fuzzy, non consistent, backup. The Use Case for ABARS is when you need to create a data consistent backup of a set of data that can be used to recover that entire set of data to the same point in time. As was mentioned in another append, an example is backing up an entire Payroll application that can be recovered in it's entirety with a single recovery command. After 9/11, I visited a client who was setting up ABARS just for Payroll because they wanted to guarantee that they could pay their employees after a disaster... If you want you employees to show up after a disaster... you better be sure that you can pay them. (In this case, ABARS was being used to protect against physical data loss). ABARS also allows you to recover one or more individual files from the aggregate backup. When mirroring alternatives are too expensive, ABARS can be used as a lower cost DR solution that clients use as follows: For backups, full volume dumps are created for the system packs and ABARS is used to backup all of the various applications and their related data. DR tests are performed by renting space at an offsite facility. The first step is to recover all of the system packs and start the system. They then recover the remainder of their data by prioritizing the ABARS recoveries. They start with their most critical applications and bring them up as the recoveries complete. So, when determining your backup strategy, first determine your recovery needs and then determine which backup technique will best fit those needs. Glenn Wilcock DFSMShsm Architect ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
