POHMELFS vs NFS: dbench and the power of the local metadata cache
POHMELFS vs NFS dbench performance
Client and server machines have 8Gb of RAM and I ran single-threaded test to show the power of the local metadata cache, so get this data with a fair grain of salt.
POHMELFS served close to 160k operations over the network, while async in-kernel NFS ended up with this dump:
1 643930 23.31 MB/sec execute 149 sec 1 649695 23.37 MB/sec cleanup 150 sec /bin/rm: cannot remove directory `/mnt//clients/client0/~dmtmp/ACCESS': Directory not empty /bin/rm: cannot remove directory `/mnt//clients/client0/~dmtmp/SEED': Directory not empty 1 649695 23.36 MB/sec cleanup 150 sec
More precise performance values:
POHMELFS 652.481 MB/sec NFS 23.366 MB/sec
I’ve pushed POHMELFS update to the GIT, which includes a long-waiting switch from the own path cache to the system’s dcache (kudos to the one who exported
dcache_lock to the modules :)
It will be likely pushed into the
drivers/staging in a day or so.