> Op 3 februari 2017 om 9:07 schreef Ahmed Khuraidah <abushihab@xxxxxxxxx>: > > > Thank you guys, > > I tried to add option "exec_prerun=echo 3 > /proc/sys/vm/drop_caches" as > well as "exec_prerun=echo 3 | sudo tee /proc/sys/vm/drop_caches", but > despite FIO corresponds that command was executed, there are no changes. > Try a reboot in between, that way you are sure the cache is clean. > But, I caught very strange another behavior. If I will run my FIO test > (speaking about 3G file case) twice, after the first run FIO will create my > file and print a lot of IOps as described already, but if- before second > run- drop cache (by root echo 3 > /proc/sys/vm/drop_caches) I broke will > end with broken MDS: > That's not good! The MDS should not crash. What kernel version are you using as a client on which OS? $ lsb_release -a $ uname -a Wido > --- begin dump of recent events --- > 0> 2017-02-03 02:34:41.974639 7f7e8ec5e700 -1 *** Caught signal > (Aborted) ** > in thread 7f7e8ec5e700 thread_name:ms_dispatch > > ceph version 10.2.4-211-g12b091b (12b091b4a40947aa43919e71a318ed0dcedc8734) > 1: (()+0x5142a2) [0x557c51e092a2] > 2: (()+0x10b00) [0x7f7e95df2b00] > 3: (gsignal()+0x37) [0x7f7e93ccb8d7] > 4: (abort()+0x13a) [0x7f7e93ccccaa] > 5: (ceph::__ceph_assert_fail(char const*, char const*, int, char > const*)+0x265) [0x557c51f133d5] > 6: (MutationImpl::~MutationImpl()+0x28e) [0x557c51bb9e1e] > 7: (std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release()+0x39) > [0x557c51b2ccf9] > 8: (Locker::check_inode_max_size(CInode*, bool, bool, unsigned long, bool, > unsigned long, utime_t)+0x9a7) [0x557c51ca2757] > 9: (Locker::remove_client_cap(CInode*, client_t)+0xb1) [0x557c51ca38f1] > 10: (Locker::_do_cap_release(client_t, inodeno_t, unsigned long, unsigned > int, unsigned int)+0x90d) [0x557c51ca424d] > 11: (Locker::handle_client_cap_release(MClientCapRelease*)+0x1cc) > [0x557c51ca449c] > 12: (MDSRank::handle_deferrable_message(Message*)+0xc1c) [0x557c51b33d3c] > 13: (MDSRank::_dispatch(Message*, bool)+0x1e1) [0x557c51b3c991] > 14: (MDSRankDispatcher::ms_dispatch(Message*)+0x15) [0x557c51b3dae5] > 15: (MDSDaemon::ms_dispatch(Message*)+0xc3) [0x557c51b25703] > 16: (DispatchQueue::entry()+0x78b) [0x557c5200d06b] > 17: (DispatchQueue::DispatchThread::entry()+0xd) [0x557c51ee5dcd] > 18: (()+0x8734) [0x7f7e95dea734] > 19: (clone()+0x6d) [0x7f7e93d80d3d] > NOTE: a copy of the executable, or `objdump -rdS <executable>` is needed > to interpret this. > " > > On Thu, Feb 2, 2017 at 9:30 PM, Shinobu Kinjo <skinjo@xxxxxxxxxx> wrote: > > > You may want to add this in your FIO recipe. > > > > * exec_prerun=echo 3 > /proc/sys/vm/drop_caches > > > > Regards, > > > > On Fri, Feb 3, 2017 at 12:36 AM, Wido den Hollander <wido@xxxxxxxx> wrote: > > > > > >> Op 2 februari 2017 om 15:35 schreef Ahmed Khuraidah < > > abushihab@xxxxxxxxx>: > > >> > > >> > > >> Hi all, > > >> > > >> I am still confused about my CephFS sandbox. > > >> > > >> When I am performing simple FIO test into single file with size of 3G I > > >> have too many IOps: > > >> > > >> cephnode:~ # fio payloadrandread64k3G > > >> test: (g=0): rw=randread, bs=64K-64K/64K-64K/64K-64K, ioengine=libaio, > > >> iodepth=2 > > >> fio-2.13 > > >> Starting 1 process > > >> test: Laying out IO file(s) (1 file(s) / 3072MB) > > >> Jobs: 1 (f=1): [r(1)] [100.0% done] [277.8MB/0KB/0KB /s] [4444/0/0 iops] > > >> [eta 00m:00s] > > >> test: (groupid=0, jobs=1): err= 0: pid=3714: Thu Feb 2 07:07:01 2017 > > >> read : io=3072.0MB, bw=181101KB/s, iops=2829, runt= 17370msec > > >> slat (usec): min=4, max=386, avg=12.49, stdev= 6.90 > > >> clat (usec): min=202, max=5673.5K, avg=690.81, stdev=361 > > >> > > >> > > >> But if I will change size to file to 320G, looks like I skip the cache: > > >> > > >> cephnode:~ # fio payloadrandread64k320G > > >> test: (g=0): rw=randread, bs=64K-64K/64K-64K/64K-64K, ioengine=libaio, > > >> iodepth=2 > > >> fio-2.13 > > >> Starting 1 process > > >> Jobs: 1 (f=1): [r(1)] [100.0% done] [4740KB/0KB/0KB /s] [74/0/0 iops] > > [eta > > >> 00m:00s] > > >> test: (groupid=0, jobs=1): err= 0: pid=3624: Thu Feb 2 06:51:09 2017 > > >> read : io=3410.9MB, bw=11641KB/s, iops=181, runt=300033msec > > >> slat (usec): min=4, max=442, avg=14.43, stdev=10.07 > > >> clat (usec): min=98, max=286265, avg=10976.32, stdev=14904.82 > > >> > > >> > > >> For random write test such behavior not exists, there are almost the > > same > > >> results - around 100 IOps. > > >> > > >> So my question: could please somebody clarify where this caching likely > > >> happens and how to manage it? > > >> > > > > > > The page cache of your kernel. The kernel will cache the file in memory > > and perform read operations from there. > > > > > > Best way is to reboot your client between test runs. Although you can > > drop kernel caches I always reboot to make sure nothing is cached locally. > > > > > > Wido > > > > > >> P.S. > > >> This is latest SLES/Jewel based onenode setup which has: > > >> 1 MON, 1 MDS (both data and metadata pools on SATA drive) and 1 OSD > > (XFS on > > >> SATA and journal on SSD). > > >> My FIO config file: > > >> direct=1 > > >> buffered=0 > > >> ioengine=libaio > > >> iodepth=2 > > >> runtime=300 > > >> > > >> Thanks > > >> _______________________________________________ > > >> ceph-users mailing list > > >> ceph-users@xxxxxxxxxxxxxx > > >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > _______________________________________________ > > > ceph-users mailing list > > > ceph-users@xxxxxxxxxxxxxx > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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