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 > > >
