topic Large swap space on Integrity server in Operating System - Linux

Large swap space on Integrity server

Philip Juels_1 — Fri, 30 Sep 2005 09:31:52 GMT

We've got an rx4640 with 40GB of RAM and two 146GB drives. I intent to install RedHat AS v3 Update 5 onto the first drive and plan to use the second as a "cold mirror". If I follow the usual swap space rule of > 2xRAM, I'll have a swap partition of over 80GB. As this will be the largest partition on the drive, are there any caveats to this? Should I create smaller multiple swap partitions?

Thanks,

PJ

Re: Large swap space on Integrity server

baiju_3 — Fri, 30 Sep 2005 09:55:27 GMT

Do you have any SAN attached , in that case you can add SAN disks as secondary Swaps.

There is no special advantage which you are going to get having multiple swap parition on the same physical disk.But if you can configure mulitiple swap spaces on different disk , in that case it will improve the I/O performance .

thx,
bl.

Re: Large swap space on Integrity server

Philip Juels_1 — Fri, 30 Sep 2005 10:07:04 GMT

Thanks for the reply...

We do have a SAN (EVA-5000), but the rx4640 is not attached to it. It accesses data storage via NFS mount from the fileserver attached to the SAN.

But, you don't foresee any issues with a single locally mounted >80GB swap part? I was curious to know if there is a maximum swap size that I might bump up against.

PJ

Re: Large swap space on Integrity server

Ivan Ferreira — Fri, 30 Sep 2005 10:09:18 GMT

The larger the RAM, the less swap you need. For VLM machines, I used to use SWAP=RAM.

In VLM, SWAP sould not be used, and if is used, then again should be tuned to avoid the use.

The latest recommendation I know is to create swap space using multiple 2GB partitions. I did not found any information about if this restriction still exists for Integrity servers.

Re: Large swap space on Integrity server

Ivan Ferreira — Fri, 30 Sep 2005 10:46:35 GMT

From the Red Hat Installation manual for Itanium, is possible to see that the restriction of the 2 GB partition size for swap still applies.

http://www.redhat.com/docs/manuals/enterprise/RHEL-3-Manual/x8664-multi-install-guide/s1-diskpartitioning.html

http://www.redhat.com/docs/manuals/enterprise/

Re: Large swap space on Integrity server

Ian Derringer — Thu, 06 Oct 2005 08:55:58 GMT

My Bad!! I did not have a chance to read the RH partitioning guidlines and I've created a huge primary swap file to 24GB. Ok, that's siad and done with. How do I undo what I did without shooting my self in a foot?? Should I create a new 2Gb swap file out on the SAN and delete the first primary (24Gb) swap file?

Thank you in advance.

Ian

Re: Large swap space on Integrity server

Ivan Ferreira — Thu, 06 Oct 2005 09:20:01 GMT

I think that you should create a new vdisk, partition as should be, an use this as swap and remove the other. Reboot.

You can use the other partition by creating a filesystem on it and mounting it.

I say this because you won't be able to create too many partitions at this point in that disk.