Re: [opensuse-factory] Btrfs under heavy write makes system sluggish-er than ext

On Tue, Nov 19, 2013 at 3:09 PM, Claudio Freire wrote:

On Tue, Nov 19, 2013 at 2:59 PM, Matthias G. Eckermann wrote:

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So, at least one conclusion can be drawn from this:

Under heaving writing, btrfs induces noticeably higher read await times than ext4, resulting in the considerably sluggish system I reported initially. [...] Yes, ext4 took longer (14 minutes longer). That could be noise, the system wasn't totally idle (I was browsing with firefox, painfully slowly, but inducing some extra load). It does look though to be an I/O scheduling issue more than a performance issue, because restore times are comparable.

Well, so, in the end, btrfs was faster, but the system less responsible to user interaction. Is that the right summary?

Yep.

I think I managed to find a clue to a cause. It seems heavy write activity on btrfs partitions induces higher swappiness than the same activity in ext4. Not sure why. Decreasing swappiness moderately improved responsiveness a great deal, so this seems to be the right direction in finding a fix. -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org