Re:Things We Forgot to Monitor
by caw on Monday February 10, 2014 @03:11PM
(#7213440)
Similar to free inodes, you should also check for maximum number of directories. dir_index option helps, but I've seen it become a problem.
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There's a maximum number of directories? On what filesystem is that?
ext3 without dir_index has a limit of 32K directories in any one directory.
Where I saw it crop up was 32K folders under /tmp on a cluster system. So no it's not a limit on number of directories entirely (that's inodes), but rather how many subdirectories you can have.
http://en.wikipedia.org/wiki/Ext4#Features <-- Fixes 32K limit
ext3/4 has really poor large-directory performance, even with dir_index, especially if you are constantly removing and readding nodes. I would highly recommend XFS for large-directory use cases.