If an IBM i system has one or more independent auxiliary storage pools (IASPs) available and a Backup, Recovery & Media Services (BRMS) control group with a *LINK backup item for ASP device *ALLAVL is used to save integrated file system (IFS) objects, a single media file will be generated. The media file will contain objects from the system ASP, user ASPs and IASPs. BRMS will produce a saved item for objects in the system ASP and user ASPs and saved items for objects on each of the IASPs. Each of the saved items refer to the same media file.
This creates two problems:
1. If each of the IFS saved items are used to restore objects during the recovery without omitting any objects from the restore, each of the restores will restore the same objects.
2. If a restore of an IFS saved item includes objects that were saved from an IASP and the IASP is not available during the restore, objects from the IASP will be restored into the system ASP. This can complicate recoveries because IASPs may not be available during the early stages of a recovery.
To avoid these problems and allow for more efficient processing during recoveries, BRMS recommends that multiple saves are used to save IFS objects on systems that have IASPs.
Here are example control group entries for a system that has two IASPs (IASP1 and IASP2) configured. These control group entries will generate individual saves for ASPs and each IASP:
Recovery of IFS objects from save media that was created on systems with IASP can be complicated. To simplify the recovery, it is important to follow the guidelines on How to backup IFS objects on systems with IASPs. This will allow the commands found on your recovery report to be run without having to omit any objects during a recovery.
Warning: If the guidelines on How to backup IFS objects on systems with IASPs are not followed and only one save is used to backup IFS objects from the system ASP, user ASPs and IASPs, two critical steps must be taken in addition to the steps provided in the recovery report:
1. IASP objects must be omitted from restores done before IASPs are available during the recovery, otherwise the IFS objects that were saved from IASPs will be restored into the system ASP.
2. Only IASP objects should be restored after the IASPs are available during the recovery, otherwise the IFS objects from the system ASP and user ASPs will be restored a second time.
This information is also available on the IBM i developerWorks site, BRMS page:
- How to backup IFS objects on systems with IASPs
- How to recover IFS objects that were saved on systems with IASPs
I’d like to thank MJ Thompson on the BRMS team for this blog; he has been involved with IBM i backup and recovery development for 20+ years and specifically with Backup, Recovery and Media Services for the past several years.
This blog post was originally published on IBMSystemsMag.com and is reproduced here by permission of IBM Systems Media.