onbar question

I am a little confused regarding the difference between a whole-system backup and a dbspace backup which backs up all dbspaces. If all my disks get blown away, can I use my dbspace backup (all dbspaces) to rebuild the database, or must I have a whole-system backup to recover? The onbar manual seems to be a bit vague about this, but the IECC manual explicitly states that you must have a whole-system backup: "- Whole system restore. Replaces all data necessary to restore your database server, including dbspaces, blobspaces, system tables, and logical log transactions. - Database space restore. Replaces all data necessary to restore the selected dbspace or blobspace. Critical dbspaces must be restored by performing a whole system restore." Thanks Gabor Heppes IBM GSA gaborh@au1.ibm.com -----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own

You can restore just fine from a dbspace-level backup, just so long as you've got all of the dbspaces backed up. We've done full restores before, and we've never done a '-w' backup or restore. It's just critical that you have all of the dbspaces, including the criticals, backing up. I've always found the -w option to be less than useful. Among other things, it precludes parallelism of backups (although we don't use parallelism at our site). The only rule I'm aware of is that if you back up using -w, you must restore using -w. Gabor Heppes wrote in message <7dc746$biv$1@nnrp1.dejanews.com>... >I am a little confused regarding the difference between a whole-system backup >and a dbspace backup which backs up all dbspaces. > >If all my disks get blown away, can I use my dbspace backup (all dbspaces) to >rebuild the database, or must I have a whole-system backup to recover? The >onbar manual seems to be a bit vague about this, but the IECC manual >explicitly states that you must have a whole-system backup: > >"- Whole system restore. Replaces all data necessary to restore your > database server, including dbspaces, blobspaces, system tables, and > logical log transactions. > - Database space restore. Replaces all data necessary to restore the > selected dbspace or blobspace. Critical dbspaces must be restored by > performing a whole system restore." > >Thanks > >Gabor Heppes >IBM GSA >gaborh@au1.ibm.com > >-----------== Posted via Deja News, The Discussion Network ==---------- >http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own

On Thu, 25 Mar 1999 09:24:09 -0500, "Thomas J. Girsch" wrote: >I've always found the -w option to be less than useful. Among other things, >it precludes parallelism of backups (although we don't use parallelism at >our site). > >The only rule I'm aware of is that if you back up using -w, you must restore >using -w. However, a -w backup is more or less the only type that can be restored from without applying logical log backups afterwards. If you are not backing up your logical logs as well, a dbspace backup will be useless. I say "more or less" because technically, you can restore from a dbspace backup without logical logs IF AND ONLY IF: the dbspace backup includes all dbspaces and blobspaces; and BAR_MAX_BACKUP is set to a value of 1. This is essentially a non-parallel backup of all spaces, which is functionally the same as a whole system backup (-w). If you are doing backups in that fashion, you may as well do whole system backups! Dave

Again, not true. You do have to trick it, however. Basically, if you don't want to do a logical log restore (just the backup), you edit the ixbar file to delete any references to logical logs that completed after the full backup (or last incremental) STARTED. Then when it goes to do a logical recovery, it will see that there aren't any logs to be restored, and you're all set. It will just do an empty logical recovery after the physical recovery completes. You might be right about needing to set BAR_MAX_BACKUP to 1. And you're absolutely right about needing all of the dbspaces, including criticals (thought I mentioned that). David Kosenko wrote in message <36fb6925.5752119@nntp.best.ix.netcom.com>... >On Thu, 25 Mar 1999 09:24:09 -0500, "Thomas J. Girsch" wrote: >>I've always found the -w option to be less than useful. Among other things, >>it precludes parallelism of backups (although we don't use parallelism at >>our site). >> >>The only rule I'm aware of is that if you back up using -w, you must restore >>using -w. > >However, a -w backup is more or less the only type that can be >restored from without applying logical log backups afterwards. If you >are not backing up your logical logs as well, a dbspace backup will be >useless. > >I say "more or less" because technically, you can restore from a >dbspace backup without logical logs IF AND ONLY IF: the dbspace backup >includes all dbspaces and blobspaces; and BAR_MAX_BACKUP is set to a >value of 1. This is essentially a non-parallel backup of all spaces, >which is functionally the same as a whole system backup (-w). If you >are doing backups in that fashion, you may as well do whole system >backups! > >Dave >

I should point out (as David pointed out to me) that editing the ixbar file is not supported by Informix. And if you should try it, by all means back up the ixbar file before you edit it!! You can accomplish the same idea by using a point-in-time restore, to a point just after the last L0/L1 to be restored STARTED. Thomas J. Girsch wrote in message <36fa846e.0@newsfeed.one.net>... >Again, not true. You do have to trick it, however. Basically, if you don't >want to do a logical log restore (just the backup), you edit the ixbar file >to delete any references to logical logs that completed after the full >backup (or last incremental) STARTED. Then when it goes to do a logical >recovery, it will see that there aren't any logs to be restored, and you're >all set. It will just do an empty logical recovery after the physical >recovery completes. > >You might be right about needing to set BAR_MAX_BACKUP to 1. And you're >absolutely right about needing all of the dbspaces, including criticals >(thought I mentioned that). > >David Kosenko wrote in message <36fb6925.5752119@nntp.best.ix.netcom.com>... >>On Thu, 25 Mar 1999 09:24:09 -0500, "Thomas J. Girsch" wrote: >>>I've always found the -w option to be less than useful. Among other >things, >>>it precludes parallelism of backups (although we don't use parallelism at >>>our site). >>> >>>The only rule I'm aware of is that if you back up using -w, you must >restore >>>using -w. >> >>However, a -w backup is more or less the only type that can be >>restored from without applying logical log backups afterwards. If you >>are not backing up your logical logs as well, a dbspace backup will be >>useless. >> >>I say "more or less" because technically, you can restore from a >>dbspace backup without logical logs IF AND ONLY IF: the dbspace backup >>includes all dbspaces and blobspaces; and BAR_MAX_BACKUP is set to a >>value of 1. This is essentially a non-parallel backup of all spaces, >>which is functionally the same as a whole system backup (-w). If you >>are doing backups in that fashion, you may as well do whole system >>backups! >> >>Dave >> > >