DB Backup Time

[danishgambit]

Morning,

Progress v10.2B on redhat.

got a strange situation and hoping that I might get some suggestions from this forum.

We use 3 production databases for each of our customers and do a full online backup every evening. Checking the logfiles shows that the smallest of the 3 databases is taking about twice as long to backup. Just wondering what could be causing this from a database point of view. I know there could be many other reasons relating to the operating system and environment, but we've moved the time of the backups about and still get the same results

"Backed up 9009111 db blocks in 00:34:29"
"Backed up 3882994 db blocks in 00:58:07" << this database is less than half the size but takes a lot longer >>
"Backed up 9085840 db blocks in 00:39:21"

Just wondering if anyone has come across something like this before ?

TIA,

DanishGambit.

 

[RealHeavyDude]

For one it depends on how much update activity is happening on the database while the online backup is running. If no update activity happens the utility can back up the database blocks almost sequentially whereas if there is update activity it needs to hop around all over the place to back up the database blocks due to be updated out of sequence.

Heavy Regards, RealHeavyDude.

 

[TomBascom]

Your disk subsystem also makes a big difference. You could, for instance, have one of those crazy arrangements where supposedly less active data gets quietly moved to RAID5. And we all know what that means

 

[danishgambit]

Afternoon,

thanks for the responses - just back from christmas break hence delay in responding. I should have mentioned that the database in question holds only lobs, so I was hoping / expecting that would be the reason. WRT your replies - there's very little other activity occuring in the box during the backup and we're using RAID 10 (so hopefully this shouldn't cause any adverse issues).

Regards,

DG

 

[TomBascom]

LOBs are infamously not counted by some utilities.

Are you sure that that database is half the size of the others? Is the backup file half the size?

Have you tried adding -com to your probkup parameters?

 

[repostor]

If you use Linux / Unix operating system, than you can check the resource utilization from /var/log/sa or /var/adm/sa using the sar command.