Formula to calculate memory needed for a given nfile

[thewho?]

Hello,
HP-UX 11.0, N4000
We're on a special situation where we might need to have a lot of files open (>200) for every user (>500) in our box. Does anybody know how many bytes per nfile the system reserves?
Thanks in Advance,
Luis

[James R. Ferguson]

Hi Luis:

I don't know exactly how many bytes each entry requires, but the documentation ( http://docs.hp.com/hpux/onlinedocs/os/KCparam.Nfile.html ) for nfile notes "...Be generous with this number because the required memory is minimal...".

...JRF...

[A. Clay Stephenson · Accepted solution]

I remember the value from older releases was 28 bytes and I doubt very much that it has increased very much with 11.x. I would be very liberal with this setting. I often exceed 10000
and sometimes go much higher.

[A. Clay Stephenson]

I just found a reference which states that 32 slots occupy approximately 1KB which would indicate that each nfile entry uses 32 bytes of kernel space.

[thewho?]

Thanks to all of you for your quick response.
We currently have the nfile set at 160,000 which will amount to 5Mb of memory within the kernel. The value we estimate we need would be close to 500,000 (which will reserve 16Mb).
According to glance (option m) we're currently allocating 307 Mb for the kernel (Sys Mem field), this increase in nfiles would represent a 5% increase on the kernel, which, to me, shouldn't impact that much.
What would be the repercusions of such a value?
Am I reading this right?
TIA,
Luis