archecker utility on ontape level 1 archive

Hi, when I run the archecker utility on a level 0 archive taken with ontape, it runs fine and gives me PASSED and exits 0. When I run it on a subsequent level 1 archive, I get numerous errors. Should archecker also work on level 1 backups? Upon request I can paste the archecker output. Thanks and best regards, Arjen Van Drie. ------------------------------ Arjen Van Drie ------------------------------ #Informix

Hi Arjen, Are you first restoring level 0 and then level 1. As far as i know, Archecker refer the L0 backup as baseline and perform log rollforward restore until given time which is from L1 backup. Or you are directly restoring from L-1 backup? Regards, Gaurav ------------------------------ Gaurav Kumar ------------------------------

Hello Gaurav, I am not restoring; I am using archecker to verify the integrity of a backup archive, which is, as far as I understood, one of archecker's purposes. Best, Arjen. ------------------------------ Arjen Van Drie ------------------------------

Hello Arjen, Can you please let me know the command you are running and the error log which you are getting. Becuase i think with archecker you can verify your backup Regards Gaurav ------------------------------ Gaurav Kumar ------------------------------

Hi Arjen, backup verification indeed is one, in fact the original purpose of the archecker utility (even though it nowadays looks to be going by "table level restore utility"), and it still would the utility of choice for ontape backups (while 'onbar -v' would be what you'd use for onbar backups - which in turn would again invoke archecker under the hood.) On the question of L 0|1|2 backup verification: only L 0 backups contain what's required to conduct verification, so an ontape L 1 backup alone would be nothing archecker could work with (and there's no way to combine L 0|1|2 backups to a workable entity.) I'm not sure 'onbar -v' would be smarter, but would assume it is not. HTH, Andreas ------------------------------ Andreas Legner ------------------------------

Hello Andreas, that is what I already feared. There apparently is no other way to verify if a level 1 or 2 backup went well than by checking the exit status of the ontape command, and also by reading (parsing) what ontape prints afterwards, being something similar to "Read/Write End Of Medium [...] Program over." Thanks for your answer, it helps :) Best, Arjen. ------------------------------ Arjen Van Drie ------------------------------

The only sure way is to do a test restore and verify 1) The engine comes online 2) Very recent data in the source server is indeed in the restore. Also please please dd (or equivalent) /dev/zero or /dev/random over the chunks before each restore test. Those of you old enough to remember the SCO icc issue will know why. - Clive Eisen

Good suggestion to test restore to pristine or zero'd out drives/files. Don't forget that prior to SE v5.08 archives would miss pages on a very busy system! It wasn't found until someone (OK me) needed to restore to clean disks and not over a partially corrupted system where the holes in the archive were filled in by prior existing content. <sigh> Informix was also testing their archives by restoring the same instance to the same drives over and over (as was I at the time) so it wasn't picked up until it bit me! ------------------------------ Art S. Kagel, President and Principal Consultant ASK Database Management Corp. www.askdbmgt.com ------------------------------

Of course a restore and verification is the only sure way, but I would not do that every time I take a backup: it would take too many resources from my team. So every once in a while a full restore (on zeroed files/disks, thanks for the suggestion), but for the daily backup I will check ontape's exit status for level 1 and 2 archives. Archecker still looks like a good choice for level 1 backups. Arjen. ------------------------------ Arjen Van Drie ------------------------------

OOps, clarification it wasn't SE that had the archive "holes" problem but OnLine thoruhg v5.07 fixed in 5.08. Art ------------------------------ Art S. Kagel, President and Principal Consultant ASK Database Management Corp. www.askdbmgt.com ------------------------------