shmmax setting

[Adam Noble]

Hi all,

Can anyone tell me why I can't set my shmmax setting to 17179869184 on one server with 2GB of memory. Yet on other servers with similar physical memory sizings I can. I can see the logic in the fact we don't have the physical memory but SAP complains unless it is set to this. More critically why is it only this server that seems to complain???

Cheerxs

[Peter Godron]

Hi,
are you sure you want to allow ANY process to get upto nearly 17Gb of virtual memory ?

[Adam Noble]

Totally agree Peter its not really that logical. Its more the fact that its set like this on other servers. I have done some more digging and its apparently a patch which is 30196. It clearly is an inapropriate setting however and will investigate.

[Andrew Merritt_2]

Hi Adam,

You don't say which version of HP-UX you have, but I would guess it's 11.11 (11i v1). How are you trying to set shmmax?

PHKL_30196, which is for 11.11, does contain the fix for the following, which may well be the answer:

( SR:8606177377 CR:JAGad46609 )
SAM will not allow setting the VM tunable SHMMAX above the 32-bit maximum of 0x40000000 on 64-bit kernels, when the documentation (and design) specifies a 64-bit limit of 0x40000000000. Also, SAM will attempt to lower the value of SHMMAX back to the lower maximum if it has been raised to a higher value by other means.

Andrew