Exact as in our case. Ilya, same for images from our side. Headers opened from hot tier
пятница, 21 августа 2015 г. пользователь Ilya Dryomov написал: > On Fri, Aug 21, 2015 at 2:02 AM, Samuel Just <sj...@redhat.com > <javascript:;>> wrote: > > What's supposed to happen is that the client transparently directs all > > requests to the cache pool rather than the cold pool when there is a > > cache pool. If the kernel is sending requests to the cold pool, > > that's probably where the bug is. Odd. It could also be a bug > > specific 'forward' mode either in the client or on the osd. Why did > > you have it in that mode? > > I think I reproduced this on today's master. > > Setup, cache mode is writeback: > > $ ./ceph osd pool create foo 12 12 > *** DEVELOPER MODE: setting PATH, PYTHONPATH and LD_LIBRARY_PATH *** > pool 'foo' created > $ ./ceph osd pool create foo-hot 12 12 > *** DEVELOPER MODE: setting PATH, PYTHONPATH and LD_LIBRARY_PATH *** > pool 'foo-hot' created > $ ./ceph osd tier add foo foo-hot > *** DEVELOPER MODE: setting PATH, PYTHONPATH and LD_LIBRARY_PATH *** > pool 'foo-hot' is now (or already was) a tier of 'foo' > $ ./ceph osd tier cache-mode foo-hot writeback > *** DEVELOPER MODE: setting PATH, PYTHONPATH and LD_LIBRARY_PATH *** > set cache-mode for pool 'foo-hot' to writeback > $ ./ceph osd tier set-overlay foo foo-hot > *** DEVELOPER MODE: setting PATH, PYTHONPATH and LD_LIBRARY_PATH *** > overlay for 'foo' is now (or already was) 'foo-hot' > > Create an image: > > $ ./rbd create --size 10M --image-format 2 foo/bar > $ sudo ./rbd-fuse -p foo -c $PWD/ceph.conf /mnt > $ sudo mkfs.ext4 /mnt/bar > $ sudo umount /mnt > > Create a snapshot, take md5sum: > > $ ./rbd snap create foo/bar@snap > $ ./rbd export foo/bar /tmp/foo-1 > Exporting image: 100% complete...done. > $ ./rbd export foo/bar@snap /tmp/snap-1 > Exporting image: 100% complete...done. > $ md5sum /tmp/foo-1 > 83f5d244bb65eb19eddce0dc94bf6dda /tmp/foo-1 > $ md5sum /tmp/snap-1 > 83f5d244bb65eb19eddce0dc94bf6dda /tmp/snap-1 > > Set the cache mode to forward and do a flush, hashes don't match - the > snap is empty - we bang on the hot tier and don't get redirected to the > cold tier, I suspect: > > $ ./ceph osd tier cache-mode foo-hot forward > *** DEVELOPER MODE: setting PATH, PYTHONPATH and LD_LIBRARY_PATH *** > set cache-mode for pool 'foo-hot' to forward > $ ./rados -p foo-hot cache-flush-evict-all > rbd_data.100a6b8b4567.0000000000000002 > rbd_id.bar > rbd_directory > rbd_header.100a6b8b4567 > bar.rbd > rbd_data.100a6b8b4567.0000000000000001 > rbd_data.100a6b8b4567.0000000000000000 > $ ./rados -p foo-hot cache-flush-evict-all > $ ./rbd export foo/bar /tmp/foo-2 > Exporting image: 100% complete...done. > $ ./rbd export foo/bar@snap /tmp/snap-2 > Exporting image: 100% complete...done. > $ md5sum /tmp/foo-2 > 83f5d244bb65eb19eddce0dc94bf6dda /tmp/foo-2 > $ md5sum /tmp/snap-2 > f1c9645dbc14efddc7d8a322685f26eb /tmp/snap-2 > $ od /tmp/snap-2 > 0000000 000000 000000 000000 000000 000000 000000 000000 000000 > * > 50000000 > > Disable the cache tier and we are back to normal: > > $ ./ceph osd tier remove-overlay foo > *** DEVELOPER MODE: setting PATH, PYTHONPATH and LD_LIBRARY_PATH *** > there is now (or already was) no overlay for 'foo' > $ ./rbd export foo/bar /tmp/foo-3 > Exporting image: 100% complete...done. > $ ./rbd export foo/bar@snap /tmp/snap-3 > Exporting image: 100% complete...done. > $ md5sum /tmp/foo-3 > 83f5d244bb65eb19eddce0dc94bf6dda /tmp/foo-3 > $ md5sum /tmp/snap-3 > 83f5d244bb65eb19eddce0dc94bf6dda /tmp/snap-3 > > I first reproduced it with the kernel client, rbd export was just to > take it out of the equation. > > > Also, Igor sort of raised a question in his second message: if, after > setting the cache mode to forward and doing a flush, I open an image > (not a snapshot, so may not be related to the above) for write (e.g. > with rbd-fuse), I get an rbd header object in the hot pool, even though > it's in forward mode: > > $ sudo ./rbd-fuse -p foo -c $PWD/ceph.conf /mnt > $ sudo mount /mnt/bar /media > $ sudo umount /media > $ sudo umount /mnt > $ ./rados -p foo-hot ls > rbd_header.100a6b8b4567 > $ ./rados -p foo ls | grep rbd_header > rbd_header.100a6b8b4567 > > It's been a while since I looked into tiering, is that how it's > supposed to work? It looks like it happens because rbd_header op > replies don't redirect? > > Thanks, > > Ilya >
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