Re: About these IPC parameters

The IPC killer is that different OS's have different methods for
changing kernel parameters, and some have different kernel parameter
names.

> Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
> > Tom Lane writes:
> >> Other than shooting yourself in the foot by having SEMA or SHMEM be
> >> 0 (OFF), it looks like the parameters that could need raising on this
> >> platform would be SEMMAP, SEMMNI, SEMMNS, SHMMAX.
>
> > Can you give me a couple of lines on how to change them (e.g., edit some
> > file and reboot) and perhaps a comment whether some of these tend to be
> > too low in the default configuration?
>
> On HPUX the usual advice is "use SAM" (System Administration Manager).
> It's a pretty decent point-and-drool tool. You go into Kernel
> Configuration / Configurable Parameters and double-click on the items
> you don't like in the resulting list. When you're done, hit Create
> A New Kernel. SAM used to have some memorable deficiencies (I still
> recall that when I first used it, if you let it create a user's home
> directory it would leave /users world-writable...) but it seems reliable
> enough in HPUX 10.
>
> If I've found the right file to look at, the factory defaults are
>
> semmni 64 Number of Semaphore Identifiers
> semmns 128 Max Number of Semaphores
> shmmax 0x4000000 Max Shared Mem Segment (bytes)
> shmmni 200 Number of Shared Memory Identifiers
> shmseg 120 Shared Memory Segments per Process
>
> so you'd need to raise these to run a big installation (more than,
> say, 100 backends) but not for a default-sized setup.
>
> What I tend to want to raise are not the IPC parameters but
>
> maxdsiz 0x04000000 Max Data Segment Size (bytes)
> maxssiz 0x00800000 Max Stack Segment Size (bytes)
> maxfiles 60 Soft File Limit per Process
> maxfiles_lim 1024 Hard File Limit per Process
> maxuprc 75 Max Number of User Processes (per user)
> maxusers 32 Value of MAXUSERS macro
> nfile (16*(NPROC+16+MAXUSERS)/10+32+2*(NPTY+NSTRPTY)) Max Number of Open Files
> ninode ((NPROC+16+MAXUSERS)+32+(2*NPTY)+(10*NUM_CLIENTS)) Max Number of Open Inodes
>
> In particular, the default maxuprc would definitely be a problem for
> running a lot of backends, and you'd likely start running into nfile
> or ninode limits too.
>
> regards, tom lane
>

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