On Wed, Apr 12, 2017 at 4:28 PM, Alex Gorbachev <[email protected]>
wrote:
> Hi Ilya,
>
> On Wed, Apr 12, 2017 at 4:58 AM Ilya Dryomov <[email protected]> wrote:
>>
>> On Tue, Apr 11, 2017 at 3:10 PM, Alex Gorbachev <[email protected]>
>> wrote:
>> > Hi Ilya,
>> >
>> > On Tue, Apr 11, 2017 at 4:06 AM, Ilya Dryomov <[email protected]>
>> > wrote:
>> >> On Tue, Apr 11, 2017 at 4:01 AM, Alex Gorbachev
>> >> <[email protected]> wrote:
>> >>> On Mon, Apr 10, 2017 at 2:16 PM, Alex Gorbachev
>> >>> <[email protected]> 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?
Unfortunately, short of installing a custom kernel or disabling data
CRCs entirely, yes. I'll poke the respective maintainer again later
today...
Thanks,
Ilya
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