On Tue, Oct 26, 2021 at 11:25 AM Shawn Heisey <elyog...@elyograg.org> wrote: > > On 10/26/21 8:34 AM, Michael Gibney wrote: > > In my experience, running Solr on CentOS 7 (comparable to RHEL 7) -- on > > VMWare, but "ballooning" was _not_ the issue -- I found that setting > > vm.swappiness=0 or 1 did not actually prevent swapping. Notwithstanding > > Shawn's excellent suggestions above, if you still suspect that swapping is > > the issue and you are ok with foregoing swap altogether, you might try > > straight-up `swapoff -a`. This ended up being the right choice for my case, > > fwiw. > > Not related to the OP, replying to Michael: > > I've seen some very strange behavior related to swap on Linux. My > server at home (Ubuntu 20, kernel 5.11.0) has 64GB of memory and two > 6-core CPUs. It is not running Solr. Even with what I classify as zero > memory pressure (40 or more gigabytes of memory used by OS disk > caching), and with swappiness at 0 or 1, it seems to prefer swapping out > (swap partition is 8GB) rather than just reclaiming memory from cache, > and I had thought that lowering swappiness would reverse that > preference. I haven't figured out a way to keep that from happening, > other than disabling swap. I don't need the swap space -- 64GB is more > than enough for what the server does. > > Related to the OP: > > I don't think swap is the problem. Disabling swap entirely would be a > good test to confirm. For general server use cases, I would not > recommend that action, but for dedicated systems with plenty of memory > like what is described in this thread, running without swap space seems > like a very good idea. > > Thanks, > Shawn > >
'swappiness' changed a few years ago and the values 0 and 1 are not intuitive. https://eklitzke.org/swappiness
