Not necessarily... It depends on what ends up on the swap disks. If you barely see any swap in/out activity, you don't much care how much of your swap space you are actually using. What you don't want, generally, is having lots & lots of swap in/out activity slowing the applications down (see vmstat).
So, if the request for more swap is because there are some applications with large but largely inactive memory foot prints, then extending swap is a feasible solution, but if the request is because the system is actively doing I/O on all the swap it already has, then adding more swap mostly will make it even slower, so increasing RAM would have a more beneficial effect (and higher cost). Hope this helps, WF Konynenberg On 11/21/2016 03:48 PM, Karl Kingston wrote:
I would not do that. Can you increase the guest machine size? You want to be at a point where you barely swap. From: "Beesley, Paul" <[email protected]> To: [email protected] Date: 11/21/2016 09:35 AM Subject: Additional SWAP recommendations Sent by: Linux on 390 Port <[email protected]> Hi A couple of our z/Linux servers running under z/VM are apparently short on swap space and I?ve been asked to increase it. The PROFILE EXEC has 2 SWAPGEN statements to define 2 x 768MB swap VDisks. I was planning on using defining additional Vdisk as follows: Def vfb-512 ? allocate 1GB Activate using YAST Mkswap ?f /dev/dasdx Swapon /dev/dasdx And then to add an additional SWAPGEN to the profile to make it permanent Is this the recommended method? Regards and thanks Paul Atos, Atos Consulting, Worldline and Canopy The Open Cloud Company are trading names used by the Atos group. The following trading entities are registered in England and Wales: Atos IT Services UK Limited (registered number 01245534), Atos Consulting Limited (registered number 04312380), Atos Worldline UK Limited (registered number 08514184) and Canopy The Open Cloud Company Limited (registration number 08011902). The registered office for each is at 4 Triton Square, Regent?s Place, London, NW1 3HG.The VAT No. for each is: GB232327983. This e-mail and the documents attached are confidential and intended solely for the addressee, and may contain confidential or privileged information. If you receive this e-mail in error, you are not authorised to copy, disclose, use or retain it. Please notify the sender immediately and delete this email from your systems. As emails may be intercepted, amended or lost, they are not secure. Atos therefore can accept no liability for any errors or their content. Although Atos endeavours to maintain a virus-free network, we do not warrant that this transmission is virus-free and can accept no liability for any damages resulting from any virus transmitted. The risks are deemed to be accepted by everyone who communicates with Atos by email. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
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