I have verified that by adding some debug log, and found it’s truly caused by long wait in mqueue for rejoin. but, it seems this kind laggy does no harm ? > 在 2018年3月29日，上午10:08，Yan, Zheng <ukernel@xxxxxxxxx> 写道： > > #2 0x00005555557134eb in MDCache::process_imported_caps > (this=this@entry=0x5555566a9000) at > /home/zhyan/Ceph/ceph-2/src/mds/MDCache.cc:5397 > > #3 0x00005555557149a3 in MDCache::rejoin_start > (this=this@entry=0x5555566a9000, rejoin_done_=0x5555566b5c80) at > /home/zhyan/Ceph/ceph-2/src/mds/MDCache.cc:3950 > > #4 0x0000555555663f93 in MDSRank::rejoin_start > (this=this@entry=0x5555566a8000) at > /home/zhyan/Ceph/ceph-2/src/mds/MDSRank.cc:1425 > > #5 0x00005555556747e3 in MDSRankDispatcher::handle_mds_map > (this=0x5555566a8000, m=m@entry=0x555556527400, > oldmap=oldmap@entry=0x5555564b2dc0) at > /home/zhyan/Ceph/ceph-2/src/mds/MDSRank.cc:1683 > > #6 0x0000555555655a1e in MDSDaemon::handle_mds_map > (this=this@entry=0x55555651e000, m=m@entry=0x555556527400) at > /home/zhyan/Ceph/ceph-2/src/mds/MDSDaemon.cc:1000 > > #7 0x00005555556582fc in MDSDaemon::handle_core_message > (this=this@entry=0x55555651e000, m=m@entry=0x555556527400) at > /home/zhyan/Ceph/ceph-2/src/mds/MDSDaemon.cc:1204 > > #8 0x0000555555658aa3 in MDSDaemon::ms_dispatch (this=0x55555651e000, > m=0x555556527400) at /home/zhyan/Ceph/ceph-2/src/mds/MDSDaemon.cc:1158 > > #9 0x00007fffef283eda in Messenger::ms_deliver_dispatch > (m=0x555556527400, this=0x55555651a000) at > /home/zhyan/Ceph/ceph-2/src/msg/Messenger.h:667 > > #10 DispatchQueue::entry (this=0x55555651a1a8) at > /home/zhyan/Ceph/ceph-2/src/msg/DispatchQueue.cc:201 > > #11 0x00007fffef31dcfd in DispatchQueue::DispatchThread::entry > (this=<optimized out>) at > /home/zhyan/Ceph/ceph-2/src/msg/DispatchQueue.h:101 > > #12 0x00007fffed4f336d in start_thread () from /lib64/libpthread.so.0 > > #13 0x00007fffec547b4f in clone () from /lib64/libc.so.6 > > > I think the real cause is that MDCache::process_imported_caps() takes > too long. prevent messenger from dispatch other message. > > On Thu, Mar 29, 2018 at 9:37 AM, Yan, Zheng <ukernel@xxxxxxxxx> wrote: >> On Thu, Mar 29, 2018 at 9:09 AM, 陶冬冬 <tdd21151186@xxxxxxxxx> wrote: >>> Patrick, we are using 32G memory for the mds. >>> Zheng, calling mds->heartbeat_reset() could make the healthy check pass so >>> that monitor won’t kick it out. >>> more frustrating me is about the laggy issue, from the monitor log, i can >>> actually see the MDSBeacon are sent without delay. >>> but about 50 seconds later, mds start handling that MDSBeacon message. >>> so i’m wondering would that possible the message stayed in the mqueue for >>> that long time (if the previous message is MDSMap with rejoin state, ant >>> that rejoin take long time) >>> (meantime, i will do some more investigating about this issue) >>> >> >> If it's really caused by long wait in mqueue. we should limit >> concurrent open_ino >> started by MDCache::process_imported_caps() >> >> >>> 在 2018年3月29日，上午8:10，Yan, Zheng <ukernel@xxxxxxxxx> 写道： >>> >>> On Wed, Mar 28, 2018 at 11:14 PM, 陶冬冬 <tdd21151186@xxxxxxxxx> wrote: >>> >>> Hi Zheng & Patrick, >>> >>> we are using v12.2.2. >>> Recently we’ve met an mds laggy issue (significantly, about 50 seconds) >>> i’ve traced the monitor and mds log and found that the MMDSBeacon message >>> was actually sent to mds 50 seconds ago. >>> so, looks like monitor isn’t laggy , and more worse is that i also found >>> that the mds’s health check is failed and eventually monitor >>> just kicked out this mds and make it respawn. >>> by the way, this happened at rejoin phase. >>> >>> Following is my analysis : >>> The mds health check failure is because the mds tick thread could not get >>> the mds_lock due to rejoin. (i found rejoin has many missing ino needed to >>> fetch) >>> and this leads the mqueue of the DispatchQueue consumed by Dispatcher got >>> very slow, eventually make MMDSBeacon in mqueue got dispatched after a big >>> delay. >>> >>> >>> how about calling mds->heartbeat_reset() in the loop that fetch inodes >>> >>> >>> >>> i want to know if my analysis make sense to you ? if so, i’m wondering can >>> we make MMDSBeacon fast dispatch. >>> >>> Regards, >>> Dongdong >>> >>> -- 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
