On Thu, Oct 15, 2020 at 8:20 PM Leslie Satenstein via devel <devel@xxxxxxxxxxxxxxxxxxxxxxx> wrote: > > I am looking to some performance considerations for the /etc/fstab btrs default config generated by anaconda. > > It appears to have created a subvol for root (root00) and for home (home00). > I would like to put in /opt with it's subvol, and to migrate the /var to a subvol where I can specify nodatacow. You can set nodatacow per filesystem, subvolume, directory, or file. But realize it also means no checksums and no compression. It's nice to have for very specific cases, like VM images, and not have to carve up your drive to optimize for such workloads. But I'm not sure you'll see a dramatic difference in performance outside of those specific cases. Also note that nodatacow needs to be set before the file is created. The main point of making subvolumes is to have different snapshotting policies, and possibly also different send/receive replication strategies (e.g. backup). For example some folks might consider the entirety of /var something that doesn't ver need to be snapshot or backed up. Making it a subvolume means it can have it's own regime, separate from the root subvolume. > Leaving /var as a directory under /, without specifying nodatacow concerns me as it is a very "busy" directory, and can fill up the root00 subvol quite quickly. What about nodatacow makes you think root is less likely to fill up, for a given workload? I'm not following what problem you think you might have, that you're trying to avoid. > I tried to create the two subvars, without success. I even went so far as to examine the grub menu entries. What did you try? How did it fail? > Is this not possible with Fed33 beta? Fedora doesn't apply any limitations. -- Chris Murphy _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
