Hi list,
We are suffering from OSD or OS down when there is continuing high pressure on the Ceph rack.
Basically we are on Ubuntu 12.04+ Ceph 0.56.1, 6 nodes, in each nodes with 20 * spindles + 4* SSDs as journal.(120 spindles in total)
We create a lots of RBD volumes (say 240),mounting to 16 different client machines ( 15 RBD Volumes/ client) and running DD concurrently on top of each RBD.
The issues are:
1. Slow requests
From the list-archive it seems solved in 0.56.1 but we still notice such warning
2. OSD Down or even host down
Like the message below.Seems some OSD has been blocking there for quite a long time.
Suggestions are highly appreciate.Thanks
Xiaoxi
_____________________________________________
Bad news:
I have back all my Ceph machine’s OS to kernel 3.2.0-23, which Ubuntu 12.04 use.
I run dd command (dd if=/dev/zero bs=1M count=60000 of=/dev/rbd${i} & )on Ceph client to create data prepare test at last night.
Now, I have one machine down (can’t be reached by ping), another two machine has all OSD daemon down, while the three left has some daemon down.
I have many warnings in OSD log like this:
no flag points reached
2013-01-15 19:14:22.769898 7f20a2d57700 0 log [WRN] : slow request 52.218106 seconds old, received at 2013-01-15 19:13:30.551718: osd_op(client.10674.1:1002417 rb.0.27a8.6b8b4567.000000000eba [write 3145728~524288] 2.c61810ee RETRY) currently waiting for sub ops
2013-01-15 19:14:23.770077 7f20a2d57700 0 log [WRN] : 21 slow requests, 6 included below; oldest blocked for > 1132.138983 secs
2013-01-15 19:14:23.770086 7f20a2d57700 0 log [WRN] : slow request 53.216404 seconds old, received at 2013-01-15 19:13:30.553616: osd_op(client.10671.1:1066860 rb.0.282c.6b8b4567.000000001057 [write 2621440~524288] 2.ea7acebc) currently waiting for sub ops
2013-01-15 19:14:23.770096 7f20a2d57700 0 log [WRN] : slow request 51.442032 seconds old, received at 2013-01-15 19:13:32.327988: osd_op(client.10674.1:1002418
Similar info in dmesg we have saw pervious:
[21199.036476] INFO: task ceph-osd:7788 blocked for more than 120 seconds.
[21199.037493] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[21199.038841] ceph-osd D 0000000000000006 0 7788 1 0x00000000
[21199.038844] ffff880fefdafcc8 0000000000000086 0000000000000000 ffffffffffffffe0
[21199.038848] ffff880fefdaffd8 ffff880fefdaffd8 ffff880fefdaffd8 0000000000013780
[21199.038852] ffff88081aa58000 ffff880f68f52de0 ffff880f68f52de0 ffff882017556200
[21199.038856] Call Trace:
[21199.038858] [<ffffffff8165a55f>] schedule+0x3f/0x60
[21199.038861] [<ffffffff8106b7e5>] exit_mm+0x85/0x130
[21199.038864] [<ffffffff8106b9fe>] do_exit+0x16e/0x420
[21199.038866] [<ffffffff8109d88f>] ? __unqueue_futex+0x3f/0x80
[21199.038869] [<ffffffff8107a19a>] ? __dequeue_signal+0x6a/0xb0
[21199.038872] [<ffffffff8106be54>] do_group_exit+0x44/0xa0
[21199.038874] [<ffffffff8107ccdc>] get_signal_to_deliver+0x21c/0x420
[21199.038877] [<ffffffff81013865>] do_signal+0x45/0x130
[21199.038880] [<ffffffff810a091c>] ? do_futex+0x7c/0x1b0
[21199.038882] [<ffffffff810a0b5a>] ? sys_futex+0x10a/0x1a0
[21199.038885] [<ffffffff81013b15>] do_notify_resume+0x65/0x80
[21199.038887] [<ffffffff81664d50>] int_signal+0x12/0x17
Thanks.
-chen
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