>Where did you get those numbers? I would like to read more if you can point to a link. Just found the link: https://github.com/facebook/rocksdb/wiki/Leveled-Compaction On Fri, Feb 22, 2019 at 4:22 PM Serkan Çoban <cobanserkan@xxxxxxxxx> wrote: > > >>These sizes are roughly 3GB,30GB,300GB. Anything in-between those sizes are pointless. Only ~3GB of SSD will ever be used out of a > 28GB partition. Likewise a 240GB partition is also pointless as only > ~30GB will be used. > > Where did you get those numbers? I would like to read more if you can > point to a link. > > On Fri, Feb 22, 2019 at 2:30 PM Nick Fisk <nick@xxxxxxxxxx> wrote: > > > > >On 2/16/19 12:33 AM, David Turner wrote: > > >> The answer is probably going to be in how big your DB partition is vs > > >> how big your HDD disk is. From your output it looks like you have a > > >> 6TB HDD with a 28GB Blocks.DB partition. Even though the DB used > > >> size isn't currently full, I would guess that at some point since > > >> this OSD was created that it did fill up and what you're seeing is > > >> the part of the DB that spilled over to the data disk. This is why > > >> the official recommendation (that is quite cautious, but cautious > > >> because some use cases will use this up) for a blocks.db partition is > > >> 4% of the data drive. For your 6TB disks that's a recommendation of > > >> 240GB per DB partition. Of course the actual size of the DB needed > > >> is dependent on your use case. But pretty much every use case for a > > >> 6TB disk needs a bigger partition than 28GB. > > > > > > > > >My current db size of osd.33 is 7910457344 bytes, and osd.73 is > > >2013265920+4685037568 bytes. 7544Mbyte (24.56% of db_total_bytes) vs > > >6388Mbyte (6.69% of db_total_bytes). > > > > > >Why osd.33 is not used slow storage at this case? > > > > Bluestore/RocksDB will only put the next level up size of DB on flash if the whole size will fit. > > These sizes are roughly 3GB,30GB,300GB. Anything in-between those sizes are pointless. Only ~3GB of SSD will ever be used out of a > > 28GB partition. Likewise a 240GB partition is also pointless as only ~30GB will be used. > > > > I'm currently running 30GB partitions on my cluster with a mix of 6,8,10TB disks. The 10TB's are about 75% full and use around 14GB, > > this is on mainly 3x Replica RBD(4MB objects) > > > > Nick > > > > _______________________________________________ > > 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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