Re: Help! Newbie project skidding...

Melinda McGee <melinda_mc_gee@dfci.harvard.com> wrote: >I'm working on getting a backup/recovery plan in place for a >Informix-based system a vendor is bringing in here. The vendor is giving >us the incredibly unrealistic Informix line on backups (i.e., 2 dedicated >tape drives, no background backups, etc.). We want to do a weekly level >0, nightly level 2's, and size the logical logs so that they never cycle >through all the logs between archives, so (theoretically) we don't have >to back up the logs. After each archive, we manually 'backup' the logs >and send them to /dev/null, to release them. Problem is now that during >our practice restore, we don't know how to make the recovery process use >the logs that are on-line, it appears to only want logs that are backed >up to tape. Can we do the scenario we want to? How do make the recovery >process only use the logs on-line? Our project is skidding badly because >we're scrambling to get this backup/recovery plan nailed down w/ little >vendor assistance, any help at this point would be greatly appreciated!!! > >TIA- >Melinda McGee >Lead DBA > You have not specified which version of Online you are using. I am assuming that it is pre 6.0 . Your problem may be arising because the value of LTAPEDEV when the archive was carried out is not /dev/null. Informix will assume that the log backups are to be read from LTAPEDEV (as defined at the time of the last level-0 archive); hence the insistence on using log backups that (it assumes) are on tape. Quoting from the Online administrator's manual ' Create a level-0 archive immediately after you change the value of LTAPEDEV to ensure a proper restore. ... Online Restore cannot switch tape devices as it attempts to read the logical log backup tapes.' (Page 3-49 to 3-53) IMO , I think your log backup strategy could be risky. Have you considered sending the log backups to disk? Everytime you do a level-0 archive, change the LTAPEDEV to a new file on disk and run continuous backup in the background. When you need to restore, make sure that LTAPEDEV is reset to whatever its value was at the time of the level-0 archive. As far as using the logs that are on-line for the restore, you will need to back them up first. The restore process will prompt you to back up these logs. See Page 4-35 in the Online Administrator's manual. Raj