On Feb 4, 2020, at 07:23, Åke Sandgren <ake.sandg...@hpc2n.umu.se<mailto:ake.sandg...@hpc2n.umu.se>> wrote:
When I create a large number of files on an OST and then remove them, the used inode count on the OST decreases very slowly, it takes several hours for it to go from 3M to the correct ~10k. (I'm running the io500 test suite) Is there something I can do to make it release them faster? Right now it has gone from 3M to 1.5M in 6 hours, (lfs df -i). It this the object count or the file count? Are you possibly using a lot of stripes on the files being deleted that is multiplying the work needed? These are SSD based OST's in case it matters. The MDS controls the destroy of the OST objects, so there is a rate limit, but ~700/s seems low to me, especially for SSD OSTs. You could check "lctl get_param osp.*.sync*" on the MDS to see how many destroys are pending. Also, increasing osp.*.max_rpcs_in_flight on the MDS might speed this up? It should default to 32 per OST on the MDS vs. default 8 for clients Cheers, Andreas -- Andreas Dilger Principal Lustre Architect Whamcloud
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