Hi,sage I have a question, does small files smaller than min_alloc_size will be store in RocksDB for ever? And I am not quite clear about the differences between overlay write which is set off by default and WAL write. 2016-03-07 0:34 GMT+08:00 Sage Weil <sage@xxxxxxxxxxxx>: > Hi, > > On Sun, 6 Mar 2016, 陈静 wrote: >> Hi Sage, >> >> So BlueStore will rely on RocksDB a lot, which just remind me of some >> experience regarding to LevelDB recovery and compaction some time ago. >> >> We tried Ceph RGW 0.80, which had no Bucket Index Sharding feature. SSD >> managed by FileStore is used for Bucket Index Pool. >> After we put tens of millions of files into a bucket, LevelDB of the OSD >> holding the corresponding bucket index object grew very big. >> The OSD once crashed unexpectly. When we try to start the OSD again, it took >> hours to fully get up. >> We used pstack to observed what it was doing and noticed the OSD is busy in >> recovering and compacting its LevelDB. >> The recovering and compaction consumed a lot CPU and memory as well. >> >> BlueStore seems to rely more on RocksDB, which is a variant of LevelDB. >> Then when the number of objects in BlueStore is large, will it take even >> more time for the OSD to start up (for recoverying and compaction) if it was >> not shut down cleanly previously? > > In general, rocksdb/leveldb shouldn't need to compact on startup. I'm not > sure what caused that in your situation. We've seen a few leveldb bugs in > the past that prevented compaction from happening when it should; perhaps > it was one of those. > > We did do some testing with rocksdb where we inflated the size to he db to > be very large and it performed pretty well. We didn't try clearing large > swaths of the keyspace to test the compaction side of things, though. > > sage > >> >> >> Thanks, >> Jeegn >> >> From: huang jun >> Date: 2016-03-05 18:41 >> To: Sage Weil >> CC: Dan Mick; ceph-devel >> Subject: Re: BlueStore deep-dive over bluejeans >> where to get the ppt in the video? >> >> 2016-03-03 21:19 GMT+08:00 Sage Weil <sage@xxxxxxxxxxxx>: >> > On Wed, 2 Mar 2016, Dan Mick wrote: >> >> >> >> > https://bluejeans.com/s/9dck/ >> >> >> >> Can you set this to allow download? I can't get it to play in the >> >> bluejeans interface, but downloadable files usually work for me >> > >> > Fixed! >> > >> > sage >> > -- >> > 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 >> >> >> >> -- >> thanks >> huangjun >> -- >> 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 >> >> >> -- 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
