topic Re: nfile question in Operating System - HP-UX

nfile question

Dusty Mjoen — Thu, 02 Sep 2004 12:59:57 GMT

We run an Oracle 8i database on HP-UX 11.0 on a 4-way N class. The high water mark for users is roughly 1100.

We are having to increase the nfile parameter every few months or so. We currently increase it by bumping up MAXUSERS. Currently the formula for nfile is MAXUSERS*70 + 2048. MAXUSERS = 1500

Is there any implications to continually raising this parameter? Should I be going about it a different way?

Thanks

Re: nfile question

Pete Randall — Thu, 02 Sep 2004 13:14:04 GMT

Dusty,

I would be interested in why it's increasing first. Aside from that, however, it's not a big deal. Quoting from SAM's help on configurable parameters:

" It is the number of slots in the file descriptor table. Be generous with this number because the required memory is minimal, and not having enough slots restricts system processing capacity. "

As far as how it's specified, I tend to avoid the formulas because you end up increasing values you may not have intended (or wanted) to. Your formula works out to 107048. We have ours hard coded to 114548. I suspect we could double that without any ill effects.

Pete

Re: nfile question

Sridhar Bhaskarla — Thu, 02 Sep 2004 13:14:19 GMT

Hi,

I do not use formulae at all. That's a pretty old way of doing and it is not applicable anymore in my view. For ex., increasing MAXUSERS may unnecessarily increase other parameters such as ninode which you may not want.

You can hardcode the value of nfile you want to set.

-Sri

Re: nfile question

Steven E. Protter — Thu, 02 Sep 2004 13:21:15 GMT

Free Bill Hassell HP-World tip.

He takes out those formulas in the kernel that raise other parameters based on maxusers.

I'm going to do the same. Makes sense.

Note: nfile may need to be raised, under this scenario take out the forumula and put in a number.

Also check maxuprc

That is the max number of processes for a given user. That defaults to 75 and I commonly need to bnump that up to 200 to accommodate complex Oracle products.

Either change will require a kernel compile and boot.

SEP

Re: nfile question

Dusty Mjoen — Thu, 02 Sep 2004 13:29:05 GMT

Thanks for all of the help! Sounds like hard coding is the way to go.

It increases due to the fact that the application is continually being rolled out to more users. They have added 350 users since the 1st of April, the last time I increased it.

Re: nfile question

Jeff Schussele — Thu, 02 Sep 2004 13:50:44 GMT

Hi Dusty,

The main reason that you need to increase NFILE as new users come online is that *everything* in 'NIX is a file & that includes the socket connections created by every Oracle connection.

My 2 cents,
Jeff

Re: nfile question

Bill Hassell — Thu, 02 Sep 2004 21:09:53 GMT

In a growing system, it is very normal to need nfile and nproc increased. To avoid unnecessary reboots, I would replace the formulae with a fixed value. As mentioned, MAXUSERS will affect other parameters so it is useful to break this link. If nfile is currently 15000, make it 30000. In other words, double or triple the value once you reach about 75% usage. 2x or 3x changes will allow for more growth without reboots.