VLDB Utilities Overhead 1

[TonyRoyston]

Hi all,

In connection with the really helpful scripts recently submitted for VLDB maintenance (thanks, davidmichel), can anyone give me an idea of how long the scripts might take to run, and whether they will possibly max out the processor?!!! The server needs to be able to run other foreground apps 24/7, so this is an important consideration.

Thanks.

 

[SjrH]

I worked at CA tech support up until last year and this was probably one of the most asked questions!

Its difficult to state an exact figure, but as a guideline, we stated its best to allow 1 hour per 1.5-2gb of database size. This also depended on numerous factors such as db fragmentation, speed/configuration of disk subsystem, & configuration/role of system. I've known a dbfix running on a member file/print server to take 9 hours to complete a single pass of a 16gb db. On the other hand a 12gb db running the same pass on a high spec (quad cpu, raid 0+1, ad controller) took only 2.5 hours.

If your server experiences high utilisation during the day, then I wouldn't recommend performing the commands at the same time. Again, although you can run the utilities before a backup commences, it is not recommended as they could overlap leaving the db unsynchronised and you'll have to do it all over again.

I found most people preferred to run the commands as a script over the weekend when no backups were scheduled, then, once you know how long the utilities take, you can incorporated them into your daily/weekly/monthly backup tasks.



SjrH - Data Security Storage & Availability Specialist

http://www.sjrh.co.uk