| Rich Freeman on 12 Jul 2015 12:49:57 -0700 |
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| Re: [PLUG] swappiness and ssd |
On Sun, Jul 12, 2015 at 10:14 AM, K.S. Bhaskar <bhaskar@bhaskars.com> wrote: > > The traditional view of swapping is that it is undesirable because reading > from swap is slow, and swap should therefore be used only if unavoidable. > Therefore, the received wisdom is to set a low value of swappiness, to swap > only when unavoidable, and take a performance hit when that happened. > > But, write cycle limits aside, I believe SSDs require a rethink. I'd be very interested in feedback from those using swap on SSD. However, I never thought that swapiness=0 was conventional wisdom on Linux. I can think of a million reasons why a higher setting /should/ be better. The problem is that it often isn't, and that is just due to limitations in Linux and how it is used. The defaults probably make running updatedb twice in a row a lot faster, but the problem is that nobody actually does that, and all that swapping after running it once kills everything else you do. It has been a while since I've run with swap, so it is possible that things have gotten better. I do agree that performance of swap should be much better on an SSD. The other thing I'd be concerned with is ssd write cycles. I've tried to move a lot of my heavy-modification activities off of ssd for this reason. Swap is going to tend to wear it faster. -- Rich ___________________________________________________________________________ Philadelphia Linux Users Group -- http://www.phillylinux.org Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce General Discussion -- http://lists.phillylinux.org/mailman/listinfo/plug