On Thu, 17 Jan 2013, Chen, Xiaoxi wrote: > Hi Sage? > Both CPU and Memory utilization are very low. CPU is ~ 20% (with > 60% IOWAIT), Memory is far more less . I have 32 Core Sandybridege > CPU(64 Core for HT), together with 128GB RAM per node. Hmm! > -----Original Message----- > From: Sage Weil [mailto:sage@xxxxxxxxxxx] > Sent: 2013?1?17? 0:59 > To: Andrey Korolyov > Cc: Chen, Xiaoxi; ceph-devel@xxxxxxxxxxxxxxx > Subject: Re: Ceph slow request & unstable issue > > Hi, > > On Wed, 16 Jan 2013, Andrey Korolyov wrote: > > On Wed, Jan 16, 2013 at 4:58 AM, Chen, Xiaoxi <xiaoxi.chen@xxxxxxxxx> wrote: > > > 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. There is still an issue with throttling recovery/migration traffic leading to the slow requests that should be fixed shortly. > > > 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. Oooh, you are running the kernel RBD client on a 3.2 kernel. There have been a long series of fixes since then, but we've only backported as far back as 3.4. Can you try a newer kernel version for the client? Something a recnet 3.4 or 3.7 series, like 3.7.2 or 3.4.25... Thanks! > > > 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 > > We have seen this stack trace several times over the past 6 months, but are not sure what the trigger is. In principle, the ceph server-side daemons shouldn't be capable of locking up like this, but clearly something is amiss between what they are doing in userland and how the kernel is tolerating that. Low memory, perhaps? In each case where we tried to track it down, the problem seemed to go away on its own. Is this easily reproducible in your case? > > > my 0.02$: > > http://www.mail-archive.com/ceph-devel@xxxxxxxxxxxxxxx/msg11531.html > > and kernel panic from two different hosts from yesterday during ceph > > startup(on 3.8-rc3, images from console available at > > http://imgur.com/wIRVn,k0QCS#0) leads to suggestion that Ceph may have > > been introduced lockup-alike behavior not a long ago, causing, in my > > case, excessive amount of context switches on the host leading to osd > > flaps and panic at the ip-ib stack due to same issue. > > For the stack trace my first guess would be a problem with the IB driver that is triggered by memory pressure. Can you characterize what the system utilization (CPU, memory) looks like leading up to the lockup? > > sage > N????y????b?????v?????{.n??????z??ay????????j???f????????????????:+v??????????zZ+??????"?!? -- 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
