We have to enable the mirroring to see how many files rocksdb is creating and the write amp. I am also doubting rocksdb writes coming to bluefs. All the points mentioned by Mark are valid, but i don't have the answers to them yet. I haven't spent much time on analyzing the rocksdb. Varada On Friday 08 July 2016 07:54 PM, Mark Nelson wrote: > > On 07/08/2016 09:19 AM, Igor Fedotov wrote: >> Varada, >> >> thanks a lot for detailed overview. >> >> Do I understand correctly that we are facing too large rocks db size >> that doesn't fit into allocated bluefs space? >> >> And now there is another question - why it becomes that large. > A couple of thoughts: > > 1) We need to see how well we've done with reducing the onode size. > 2) Is anything leaking into the SST files that we don't want there? > 3) How bad is the rocksdb write amp? You should be able to query > rocksdb or look at the periodic statistics in the log. We might be able > to improve it with tuning, but Allen said specifically this is an area > where Zetascale might help. > > Mark > >> >> Will try to increase db size a bit later... >> >> >> Thanks, >> >> Igor >> >> >> On 08.07.2016 16:52, Varada Kari wrote: >>> Default min allocation size on bluefs is 1MB. >>> Space consumption depends on the files created on the bluefs, if we have >>> more fnodes created on bluefs we would consume more space. >>> It depends on how many writes(new files) coming to bluefs from rocksdb >>> and space taken by the log file. >>> And for each modify/create/delete operations we log them in a file, >>> which gets compacted on each fsync from rocksdb upon meeting the >>> criteria to compact i.e; going beyond 16MB in size. >>> We try to allocate 4MB chunks for this file, to reserve some space for >>> the operation to continue. >>> In your case, we are failing to allocate 4MB for the compaction to >>> progress. >>> >>> Can you try increasing the db partition size more and try it again? >>> >>> Varada >>> >>> On Friday 08 July 2016 06:44 PM, Igor Fedotov wrote: >>>> Varada, >>>> >>>> I'm running vstart.sh hence default block db and block wal sizes: 64 M & >>>> 128 M respectively. >>>> >>>> Could you please elaborate why they go out of space - what information >>>> is being accumulated there in my case? Actually I know a little about >>>> this mechanics... >>>> >>>> Thanks, >>>> >>>> Igor >>>> >>>> >>>> On 08.07.2016 14:29, Varada Kari wrote: >>>>> Igor, >>>>> >>>>> How much is your db partition and wal partition size? >>>>> Seems you are out of space on db partition, block.db, if we go out of >>>>> space on block.db, we try to allocate block.wal. >>>>> Seems both are failing in your case and log compaction gone out of >>>>> space >>>>> for next 4MB chunk. >>>>> we shall discuss in the sync up today. >>>>> >>>>> Varada >>>>> >>>>> On Friday 08 July 2016 04:09 PM, Igor Fedotov wrote: >>>>>> Hi All, >>>>>> >>>>>> >>>>>> as I mentioned during yesterday's bluestore syncup I observed another >>>>>> issue with bluestore during random write. >>>>>> >>>>>> Here is the backtrace: >>>>>> >>>>>> 0> 2016-07-07 17:05:10.520543 7ff393dbf700 -1 >>>>>> os/bluestore/BlueFS.cc: In function 'int BlueFS::_allocate(unsigned >>>>>> int, >>>>>> uint64_t, std::vector<bluefs_extent_t>*)' thread 7ff393dbf700 time >>>>>> 2016-07-07 17:05:10.507412 >>>>>> os/bluestore/BlueFS.cc: 1398: FAILED assert(0 == "allocate >>>>>> failed... wtf") >>>>>> >>>>>> ceph version 11.0.0-289-g173e5a6 >>>>>> (173e5a6d85f624a714c0029db6f828cb1968cf3d) >>>>>> 1: (ceph::__ceph_assert_fail(char const*, char const*, int, char >>>>>> const*)+0x82) [0x7ff3a9833452] >>>>>> 2: (BlueFS::_allocate(unsigned int, unsigned long, >>>>>> std::vector<bluefs_extent_t, std::allocator<bluefs_extent_t> >>>>>>> *)+0x760) >>>>>> [0x7ff3a95186e0] >>>>>> 3: (BlueFS::_compact_log()+0xd9b) [0x7ff3a951ba8b] >>>>>> 4: (BlueFS::_maybe_compact_log()+0x2a0) [0x7ff3a951c510] >>>>>> 5: (BlueFS::sync_metadata()+0x20f) [0x7ff3a951d77f] >>>>>> 6: (BlueRocksDirectory::Fsync()+0xd) [0x7ff3a95300dd] >>>>>> 7: (rocksdb::DBImpl::WriteImpl(rocksdb::WriteOptions const&, >>>>>> rocksdb::WriteBatch*, rocksdb::WriteCallback*, unsigned long*, >>>>>> unsigned >>>>>> long, bool)+0x14e1) [0x7ff3a95ea281] >>>>>> 8: (rocksdb::DBImpl::Write(rocksdb::WriteOptions const&, >>>>>> rocksdb::WriteBatch*)+0x1b) [0x7ff3a95eae1b] >>>>>> 9: >>>>>> (RocksDBStore::submit_transaction_sync(std::shared_ptr<KeyValueDB::TransactionImpl>)+0x6b) >>>>>> >>>>>> [0x7ff3a95b7d7b] >>>>>> 10: (BlueStore::_kv_sync_thread()+0x167b) [0x7ff3a942aefb] >>>>>> 11: (BlueStore::KVSyncThread::entry()+0xd) [0x7ff3a944af5d] >>>>>> 12: (()+0x80a5) [0x7ff3a7a170a5] >>>>>> 13: (clone()+0x6d) [0x7ff3a58f9cfd] >>>>>> NOTE: a copy of the executable, or `objdump -rdS <executable>` is >>>>>> needed to interpret this. >>>>>> >>>>>> Looks like bitmap allocator returns a failure at some moment. >>>>>> >>>>>> My environment: >>>>>> >>>>>> * Ceph cluster run via vstart.sh. >>>>>> >>>>>> *rbd image created via: >>>>>> >>>>>> ./rbd create --size 1024 -c ceph.conf --image-feature layering >>>>>> fio_test >>>>>> ./rbd map -c ceph.conf fio_test >>>>>> >>>>>> * fio script is as follows: >>>>>> >>>>>> [global] >>>>>> >>>>>> [rbd_iodepth32] >>>>>> ioengine=libaio >>>>>> iodepth=32 >>>>>> filename=/dev/rbd12 >>>>>> size=1m >>>>>> io_size=8192m >>>>>> bs=128k >>>>>> rw=randwrite >>>>>> numjobs=3 >>>>>> >>>>>> >>>>>> Bug is easily reproducible with the script when bluestore allocator is >>>>>> set to bitmap (by default). I was unable to reproduce the issue with >>>>>> stupid allocator hence I suppose it's rather bitmap allocator internal >>>>>> issue. Maybe some leaks as it occurs rather by the end of the FIO >>>>>> script? >>>>>> >>>>>> One should apply bluestore patch I posted yesterday prior to >>>>>> reproduce >>>>>> this issue as one can hit another bug otherwise. >>>>>> >>>>>> >>>>>> Thanks, >>>>>> >>>>>> Igor >>>>>> >>>>>> -- >>>>>> 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 >>>>>> >>>>> PLEASE NOTE: The information contained in this electronic mail >>>>> message is intended only for the use of the designated recipient(s) >>>>> named above. If the reader of this message is not the intended >>>>> recipient, you are hereby notified that you have received this >>>>> message in error and that any review, dissemination, distribution, >>>>> or copying of this message is strictly prohibited. If you have >>>>> received this communication in error, please notify the sender by >>>>> telephone or e-mail (as shown above) immediately and destroy any and >>>>> all copies of this message in your possession (whether hard copies >>>>> or electronically stored copies). >> -- >> 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 PLEASE NOTE: The information contained in this electronic mail message is intended only for the use of the designated recipient(s) named above. If the reader of this message is not the intended recipient, you are hereby notified that you have received this message in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify the sender by telephone or e-mail (as shown above) immediately and destroy any and all copies of this message in your possession (whether hard copies or electronically stored copies). -- 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
