I am running Ubuntu 24.04 using ZFS for my filesystems. This is on a laptop whose only storage device is a WD Black SN850X NVMe card. The default Ubuntu installation process configured two ZFS pools:
capacity operations bandwidth pool alloc free read write read write-------------------------------------- ----- ----- ----- ----- ----- -----bpool 187M 1.69G 0 0 381 204 86349523-abd9-7a45-ab84-60d7622c240f 187M 1.69G 0 0 381 204-------------------------------------- ----- ----- ----- ----- ----- -----rpool 286G 634G 13 31 1.11M 796K cc31ec4d-1dd2-ed4f-9f90-fa99ec5aa3a2 286G 634G 13 31 1.11M 796K-------------------------------------- ----- ----- ----- ----- ----- -----/tmp is part of the root mount, which is in rpool.
My /tmp folder briefly had over 2 million files in it due to a bug in some code. When there were this many files in it, performance took a nosedive -- even just listing files (without sorting) would pause for upwards of a second. I removed most of the files, and things are back down to a manageable level now. But, operations on the list of files in /tmp are still slow.
When I time ls --sort=none on e.g. /bin, which has 2,842 entries it, I get something like:
real 0m0.088suser 0m0.001ssys 0m0.075sBut the same command on /tmp, which currently has 4,444 entries:
real 0m0.472suser 0m0.007ssys 0m0.446sIt seems that briefly housing 2 million files has left a permanent impact on the structure of /tmp? Is there a way to fix this? Do I just need to make a new /tmp and cut over to it??