topic Re: Changing nfile - how much downtime will result in Operating System - HP-UX

Changing nfile - how much downtime will result

Patrick Scherrer — Tue, 09 Sep 2008 18:17:25 GMT

RP3440
GB Ram
HP UX 11.11v1

I've been having issues with the file table filling and knocking down a database from time to time. I want to double the value of nfile using SAM, I understand this requires a kernel rebuild.

How much down time should I budget for that process?

Re: Changing nfile - how much downtime will result

Pete Randall — Tue, 09 Sep 2008 18:29:17 GMT

How long does it take your machine to reboot? Unless you have problems, that is all the time it should take. For something as simple as changing nfile, there shouldn't be any problems.

Pete

Re: Changing nfile - how much downtime will result

James R. Ferguson — Tue, 09 Sep 2008 18:30:17 GMT

Hi Patrick:

From an end-user perspective, I'd allow 30-minutes. This covers both shutdown; a kernel change; and startup. It's always nice to be back in service sooner than advertised.

Regards!

...JRF...

Re: Changing nfile - how much downtime will result

Rita C Workman — Tue, 09 Sep 2008 18:31:21 GMT

It only takes a few seconds to change the parm via SAM. You can do it via command line, but I like SAM for this.

Just think back to your last reboot...how long did that take? And that's all the time you'll need.

Another thing....you might want to run a few monitoring checks on parms to see if you need to adjust more than one parm. One to use is:

sar -v 1 20

This will give you proc / inode / file values. The first number in column is what is being used/the second is what parm currently is set at.
So for nfile it's under file-sz. This might give you a heads up...

Hope this helps,
Rgrds,
Rita

Re: Changing nfile - how much downtime will result

TTr — Tue, 09 Sep 2008 18:33:51 GMT

It depends. The kernel rebuild is fast, 1-3 minutes. To this you have to add the time it takes for the rp3440 to shutdown, POST and reboot. This normally is fast, about 10 minutes but it may depend on any additional applications that you may have added in the HP-UX start/stop rc sequencer. You also have to add the time it takes the database(s) to stop and restart. Assuming that your database is not extreme, it normally takes about 5-10 minutes. I would budget about 1hr but expect to take about 20-30 minutes. Keep in mind that if your database is busy, the dbshut command (assume oracle) will wait for each oracle process to finish and may take a while to shutdown.

Re: Changing nfile - how much downtime will result

Patrick Scherrer — Tue, 09 Sep 2008 18:36:12 GMT

That's what I figured but I wanted to make sure since it will be my first time with this platform.

thanks!

Re: Changing nfile - how much downtime will result

Patrick Scherrer — Tue, 09 Sep 2008 18:37:10 GMT

question answered