IDS 7.31: Backing up logical logs to disk
Posted in 2000
Topics: Backup & Restore, Server Administration, Logging & Checkpoints, Migration, Import/Export & Data Conversion, Versions, Editions & End-of-Life
Hi Informixers,
currently I'm using onbar and Legato Networker to backup IDS 7.31
logical logs to tape. This works just great, however I'm afraid that
this puts too much strain on my tapes and tape drives.
My jukebox has only two Exabyte 8mm 5/10GB drives (I know, REALLY old,
but newer equipment is not in our budget), so I cannot reserve one
drive exclusively to log backup. Since there is a lot of backup
activity especially during nighttime, the tape where the logs go
to is frequently unloaded to make room for other backups. When a
log becomes full, it is then reloaded and has to be repositioned.
I use rather small logical log files (1MB), and they become full and
have to be backed up to reuse them about 5-10 times daily during
normal database activity. I am afraid that the resulting tape un- and
reloading and frequent repositioning may be harmful to my tapes and
drives.
One alternative would be to backup the logs to disk and have the
resulting files backed up with the normal daily filesystem backup.
I tried this on another system by setting the LTAPEDEV parameter
in onconfig to a filesystem file and editing the "log_full.sh"
script to use "ontape -a" as backup command. This works, but the
filesystem file is overwritten every time a log becomes full.
Of course I could copy this file away every time it gets written,
but how do I know which log number it contains? Does anyone have
a better solution for this?
BTW: I chose to use a rather small log size so the logs will get
backed up more frequently. Are there any important reasons for not
doing so?
Regards, Richard
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Hello Richard,
Does the whole log space get full 5-10 times every day or just 5-10 single
logical log files?
Can you extend your log space? It is surely a cheaper solution than buying
a new jukebox.
You can not use onbar and ontape mixed. If you save your logical log files
onto disk with ontape, you have to use ontape to archive the database too.
So if you want to keep the comfort of onbar you HAVE to back up the logs
with it as well. It is possible even if your jukebox's throughput is low.
It is a good idea to use ALARMPROGRAM to let examine the situation after
every log switch. You can check how full your logs are and if they have
reached a threshold (e.g. 50 % or even lower!) you can start a backup.
Anyway you must prevent a situation that the the whole log space gets full
AND the jukebox has no capacity to back it up.
Regards
Peter
--
Peter Dzvonyar
SAP-Consultant R/3 BC
_______________________________________________________________
email: Peter.Dzvonyar@ops.de p.dzvonyar@t-online.de
phone: (+49) 8121 72 3583 fax: (+49) 8121 72 4996
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