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
