> Op 28 mrt. 2023 om 17:02 heeft Simon Avery <[email protected]> > het volgende geschreven: > > > Hello, > > I have a question that I’ve been struggling to get a clear answer to, or even > any indication someone has done this before, and would appreciate any > experience or thoughts. > > Are there any known issues with defining tmpdir on multiple servers to point > to a single NFS-mounted network share? Would each instance co-habit > peacefully and not try to change any files from another instance? > > > Why do I want to do this? > > I have around 80 Centos/Rocky vms which run Mariadb 10.6.x. Due to the > nature of the work they do, some of them require a significant amount of > tmpdir (up to 75Gb) relatively briefly (once or twice a day for a few minutes) > > This growth is not always predictable, so generally the first I know about it > is when Mariadb reports lowspace and the query stops. We then grow the /tmp > partition that is defined as tmpdir and if we’re quick enough, the query > completes, but often the job dies. Then that extra space stays locked away > forever, even if that server never tries to use that much tmpdir again. This > does not feel efficient and I am pondering better ways of doing this. > > One such thought would be to have a single HA NFS share on our network, > mounted onto each VM as something like /mariadb-tempdir, and set $tmpdir to > it. > > In my mind, this would make a better use of one large allocation of space > used by many things often, rather than lots of individual small to large > sized bits of space used by one thing, rarely. The chance of two or more > servers filling that space feels small, but if it happened, one would wait > until space was cleared – which might actually happen in this shared scenario > when it never does in a single-server situation. > > In my particular world, we have fast storage and a fast network. Speed tests > on large and tiny files over NFS give surprisingly similar performance to > writing to local vm disks, so I’m not worried about the overhead of NFS and > even if it was, slow might still be preferred to full.
Any reason you’re thinking of using a single share for all MariaDB machines? How about setting up a single NFS VM with lots of space, and mounting a specific directory per MariaDB machine? > > Thank you, > > Simon > _______________________________________________ > Mailing list: https://launchpad.net/~maria-discuss > Post to : [email protected] > Unsubscribe : https://launchpad.net/~maria-discuss > More help : https://help.launchpad.net/ListHelp
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