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reconfigure the kernel


reconfigure the kernel

Hi everyone

I am using tru64 unix and I want to know how to Reconfigure the kernel to have bigger segments

Martin Moore

Re: reconfigure the kernel

First question: do you mean shared memory segments? I'll assume so for the rest of this answer.

Second: what version of Tru64 are you using?

To increase the maximum shared memory segment size (the default is 4 MB), you need to define a new value for parameter shm-max (if V4) or shm_max (if V5) in /etc/sysconfigtab and reboot. This parameter is in the ipc subsystem. So you'd find the ipc: stanza in /etc/sysconfigtab (or add one if it doesn't already exist) and add a line like this:

shm_max = 8388608 (this would double the size to 8 MB).

If there is already a definition in shm_max, replace the existing value with your new one.

For V4, the maximum allowable size is 2 GB minus 1 byte, but for performance reasons it's a little better to use an exact multiple of 8 MB, so you could use up to 2 GB minus 8 MB.

For V5, the maximum allowable size is 18 exabytes or so, which is far larger than can be practically used, so it's effectively unlimited.

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