Hi Ilya,
On Wed, Apr 12, 2017 at 4:58 AM Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
On Tue, Apr 11, 2017 at 3:10 PM, Alex Gorbachev <ag@xxxxxxxxxxxxxxxxxxx> wrote:
> Hi Ilya,
>
> On Tue, Apr 11, 2017 at 4:06 AM, Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
>> On Tue, Apr 11, 2017 at 4:01 AM, Alex Gorbachev <ag@xxxxxxxxxxxxxxxxxxx> wrote:
>>> On Mon, Apr 10, 2017 at 2:16 PM, Alex Gorbachev <ag@xxxxxxxxxxxxxxxxxxx> wrote:
>>>> I am trying to understand the cause of a problem we started
>>>> encountering a few weeks ago. There are 30 or so per hour messages on
>>>> OSD nodes of type:
>>>>
>>>> ceph-osd.33.log:2017-04-10 13:42:39.935422 7fd7076d8700 0 bad crc in
>>>> data 2227614508 != exp 2469058201
>>>>
>>>> and
>>>>
>>>> 2017-04-10 13:42:39.939284 7fd722c42700 0 -- 10.80.3.25:6826/5752
>>>> submit_message osd_op_reply(1826606251
>>>> rbd_data.922d95238e1f29.00000000000101bf [set-alloc-hint object_size
>>>> 16777216 write_size 16777216,write 6328320~12288] v103574'18626765
>>>> uv18626765 _ondisk_ = 0) v6 remote, 10.80.3.216:0/1934733503, failed
>>>> lossy con, dropping message 0x3b55600
>>>>
>>>> On a client sometimes, but not corresponding to the above:
>>>>
>>>> Apr 10 11:53:15 roc-5r-scd216 kernel: [4906599.023174] libceph: osd96
>>>> 10.80.3.25:6822 socket error on write
>>>>
>>>> And from time to time, slow requests:
>>>>
>>>> 2017-04-10 13:00:04.280686 osd.91 10.80.3.45:6808/5665 231 : cluster
>>>> [WRN] slow request 30.108325 seconds old, received at 2017-04-10
>>>> 12:59:34.172283: osd_op(client.11893449.1:324079247
>>>> rbd_data.8fcdfb238e1f29.00000000000187e7 [set-alloc-hint object_size
>>>> 16777216 write_size 16777216,write 10772480~8192] 14.ed0bcdec
>>>> ondisk+write e103545) currently waiting for subops from 2,104
>>>> 2017-04-10 13:00:06.280949 osd.91 10.80.3.45:6808/5665 232 : cluster
>>>> [WRN] 2 slow requests, 1 included below; oldest blocked for >
>>>> 32.108610 secs
>>>>
>>>> Questions:
>>>>
>>>> 1. Is there any way to drill further into the "bad crc" message?
>>>> sometimes they have nothing before or after them, but how to determine
>>>> from/to what this came from - another OSD, client, which one?
>>>>
>>>> 2. Network seems OK - no errors on NICs, regression testing does not
>>>> show any issues. I realize this can be disk response, but using
>>>> Christian Balzer's atop recommendation shows a pretty normal system.
>>>> What is my best course of troubleshooting here - dump historic ops on
>>>> OSD, wireshark the links or anything else?
>>>>
>>>> 3. Christian, if you are looking at this, what would be your red flags in atop?
>>>>
>>>
>>> One more note: OSD nodes are running kernel 4.10.2-041002-generic and
>>> clients - 4.4.23-040423-generic
>>
>> Hi Alex,
>>
>> Did you upgrade the kernel client from < 4.4 to 4.4 somewhere in that time
>> frame by any chance?
>
> Yes, they were upgraded from 4.2.8 to 4.4.23 in October.
There is a block layer bug in 4.4 and later kernels [1]. It
effectively undoes krbd commit [2], which prevents pages from being
further updated while in-flight. The timeline doesn't fit though, so
it's probably unrelated -- not every workload can trigger it...
[1] http://tracker.ceph.com/issues/19275
[2] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bae818ee1577c27356093901a0ea48f672eda514
Would the workaround be to drop to 4.3?
Thank you,
Alex
Thanks,
Ilya
--
--
Alex Gorbachev
Storcium
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