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Re: Slow XFS write



Hi all,

After some research on my RAID controller, PERC H310 Mini on a Dell server, I found a lot performance issue. It does not have WriteBack cache or BBU. I do not tested to write directly on the partition because I have some backup to do before but I think reinstall the server on a software RAID is the best solution here.

Thanks to all

Le 23/08/2018 à 09:07, Stefan K a écrit :
Hello,

did you really need the hardware controller? I suggest to use Software/MD raid, ob btrfs with raid1 or zfs with raidz1

Looks suspiciously similar to LSI MegaRAID.
Is controller firmware current? Is it possible to upgrade it?
Since you seem to have BBU, have you considered enabling WriteBack mode?

Reco

Can you rebuild the partition? If so, unmount it then perform the dd directly to the device. (of=/dev/sda2 or whatever) What's the hardware raid vendor? Honestly, the performance of ext4 partition is also horrible, just not as bad as the xfs partition. What's the hardware raid model? Does it have a battery backed cache? (I will guess not, because the test is only 1G and that should fit into most current caches?) If the test directly to the partition shows good performance, then it might be an alignment issue; try recreating the fs with `mkfs.xfs -d su=64k,sw=2 ...`. If the performance is the same to the raw partition (and still much worse than the root partition) then the partition alignment itself might be off--which means recreating the partitions. (fsck and mkfs.xfs normally handle this automatically, but that depends on the raid controller+driver passing the information up, and per your xfsinfo output, that didn't happen.)

Mike Stone


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