topic Re: swap space problem in Operating System - HP-UX

swap space problem

Mihai Matei — Tue, 24 Jun 2003 15:36:49 GMT

Hi,

I modified maxswapchunks=25 , for 50 MB of swap (in order to find out how the system behaves when swap space is scarce). Well, it boots fine, but I can't modify maxswapchunks back to the previous value, because I can't recompile the new kernel (out-of-memory errors). Is there a way out of this?

(HP-UX 11.11, 256MB)

Re: swap space problem

Hai Nguyen_1 — Tue, 24 Jun 2003 15:39:43 GMT

Mihai,

You can boot your system using the previous kernel.

Interrupt the autoboot when the system is booting up then enter the ISL prompt to issue the command to boot from previous kernel.

Hai

Re: swap space problem

Pete Randall — Tue, 24 Jun 2003 15:40:27 GMT

Sure, reboot using the old kernel. Interrupt the boot process and specify vmunix.prev.

Pete

Re: swap space problem

Hai Nguyen_1 — Tue, 24 Jun 2003 15:42:15 GMT

Mihai,

This thread below can surely help you.

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xea1d5bd3782dd711abdc0090277a778c,00.html

Hai

Re: swap space problem

Mihai Matei — Tue, 24 Jun 2003 16:31:46 GMT

thank you.

Re: swap space problem

Caesar_3 — Tue, 24 Jun 2003 18:59:30 GMT

Hello!

When you compile kernel the old version saved
as vmunix.prev
so in the boot you can load it and then compile again the kernel.

Caesar

Re: swap space problem

Bill Hassell — Tue, 24 Jun 2003 22:21:32 GMT

Just a note for future testing. You don't have to reduce maxswapchunks to limit swap space. This number specifies the upper limit when you add swap space, but you can certainly define a very small primary swap area for testing. Then you can add more swap space to prevent the problem you saw when trying to create a new kernel.

Re: swap space problem

Richard Ace_1 — Wed, 25 Jun 2003 12:04:36 GMT

Yep agree to boot off your .PREV.

N.B.
The formula for Configuring SWAP is as follows.

Formula example:

MAXSWAPCHUNKS X SWCHUNKS X 1024 =
8000 X 2048 Def X 1024 = 16777216000
= 16Gb

This then sets a "maximum setting" of 16Gb's of swap allowed to be configured.

"As Bill said"

If you have secondary swap space and you want to reduce the amount of swap space you could hash out the entry in the /etc/fstab

Example

/dev/vg00/swap2 ... swap pri=2 0 0

Then reboot, the server will come back with less swap only primary configured.

Re: swap space problem

Richard Ace_1 — Wed, 25 Jun 2003 12:06:27 GMT

Configuring MAXSWAPCHUNKS sorry