On 07/30/2011 08:21 PM, Sage Weil wrote:
Hmm, looking through recent commits which will shortly be merged into
3.1, this one leaps out, but I'm not sure it's the cause --- how full
was your disk at the end of this exercise?
I haven't looked at Ceph in quite a while. As I recall it was
primarily doing Direct I/O writes, correct? Or does it use buffered
I/O? And does it use the new "punch" ioctl to release blocks from the
middle of a file? Ext4 added punch support in 3.0, and there are some
bug fixes that are going into 3.1, but I don't think there were any
that would lead to the failure mode you are seeing.
Direct-io is used for the osd journal only; is that on the ext4 partition,
Fyodor? Everything else is buffered io.
No, journal placed on tempfs.
We don't use the new punch ioctl.
We do use xattrs extensively, though; that was the last extN bug we
uncovered. That's where my money is.
Fyodor, if you set 'debug filestore = 10' you'll get a log of every
operation on the fs in the osd log. (Or close to it; there may be a few
that we missed, but to a first approximation at least it'll describe the
workload pretty well.)
Ok, I will try it. But my system fs have only 16G. I'm not sure that it
fits.
WBR,
Fyodor.
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