On Mon, 11 Jun 2012, Guido Winkelmann wrote: > Am Freitag, 8. Juni 2012, 06:55:19 schrieb Sage Weil: > > On Fri, 8 Jun 2012, Oliver Francke wrote: > > > Hi Guido, > > > > > > yeah, there is something weird going on. I just started to establish some > > > test-VM's. Freshly imported from running *.qcow2 images. > > > Kernel panic with INIT, seg-faults and other "funny" stuff. > > > > > > Just added the rbd_cache=true in my config, voila. All is > > > fast-n-up-n-running... > > > All my testing was done with cache enabled... Since our errors all came > > > from rbd_writeback from former ceph-versions... > > > > Are you guys able to reproduce the corruption with 'debug osd = 20' and > > 'debug ms = 1'? Ideally we'd like to: > > > > - reproduce from a fresh vm, with osd logs > > - identify the bad file > > - map that file to a block offset (see > > http://ceph.com/qa/fiemap.[ch], linux_fiemap.h) > > - use that to identify the badness in the log > > > > I suspect the cache is just masking the problem because it submits fewer > > IOs... > > Okay, I added 'debug osd = 20' and 'debug ms = 1' under [global] and > 'filestore fiemap = false' under [osd] and started a new VM. That worked > nicely, and the iotester found no corruptions. Then I removed 'filestore > fiemap = false' from the config, restarted all osds and ran the iotester > again. Output is as follows: > > testserver-rbd11 iotester # date ; ./iotester /var/iotest ; date > Mon Jun 11 17:34:44 CEST 2012 > Wrote 100 MiB of data in 1943 milliseconds > Wrote 100 MiB of data in 1858 milliseconds > Wrote 100 MiB of data in 2213 milliseconds > Wrote 100 MiB of data in 3441 milliseconds > Wrote 100 MiB of data in 2705 milliseconds > Wrote 100 MiB of data in 1778 milliseconds > Wrote 100 MiB of data in 1974 milliseconds > Wrote 100 MiB of data in 2780 milliseconds > Wrote 100 MiB of data in 1961 milliseconds > Wrote 100 MiB of data in 2366 milliseconds > Wrote 100 MiB of data in 1886 milliseconds > Wrote 100 MiB of data in 3589 milliseconds > Wrote 100 MiB of data in 1973 milliseconds > Wrote 100 MiB of data in 2506 milliseconds > Wrote 100 MiB of data in 1937 milliseconds > Wrote 100 MiB of data in 3404 milliseconds > Wrote 100 MiB of data in 1990 milliseconds > Wrote 100 MiB of data in 3713 milliseconds > Read 100 MiB of data in 4856 milliseconds > Digest wrong for file "/var/iotest/b45e1a59f26830fb98af1ba9ed1360106f5580aa" > Mon Jun 11 17:35:34 CEST 2012 > testserver-rbd11 iotester # ~/fiemap > /var/iotest/b45e1a59f26830fb98af1ba9ed1360106f5580aa > File /var/iotest/b45e1a59f26830fb98af1ba9ed1360106f5580aa has 1 extents: > # Logical Physical Length Flags > 0: 0000000000000000 00000000a8200000 0000000000100000 000 > > I looked into the file in question, and it started with zero-bytes from the > start until position 0xbff, even though it was supposed to all random data. > > I have included timestamps in the hopes they might make it easier to find the > related entries in the logs. > > So what do I do now? The logs are very large and complex, and I don't > understand most of what's in there. I don't even know which OSD served that > particular block/object. If you can reproduce it with 'debug filestore = 20' too, that will be better, as it will tell us what the FIEMAP ioctl is returning. Also, if you can attach/post the contents of the object itself (rados -p rbd get rb.0.1.0000000002a0 /tmp/foo) we can make sure the object has the right data (and the sparse-read operation that librbd is doing is the culprit). As for the log: First, map the offset to an rbd block. For example, taking the 'Physical' value of 00000000a8200000 from above: $ printf "%012x\n" $((0x00000000a8200000 / (4096*1024) )) 0000000002a0 Then figure out what the object name prefix is: $ rbd info <imagename> | grep prefix block_name_prefix: rb.0.1 Then add the block number, 0000000002a0 to that, e.g. rb.0.1.0000000002a0. Then map that back to an osd with $ ceph osd map rbd rb.0.1.0000000002a0 osdmap e19 pool 'rbd' (2) object 'rb.0.1.0000000002a0' -> pg 2.a2e06f65 (2.5) -> up [0,2] acting [0,2] You'll see the osd ids listed in brackets after 'active'. We want the first one, 0 in my example. The log from that OSD is what we need. Thanks! sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
