We have tested it for a while, basically it seems kind of stable but show terrible bad performance.
This is not the fault of Ceph , but levelDB, or more generally, all K-V storage with LSM design(RocksDB,etc), the LSM tree structure naturally introduce very large write amplification---- 10X to 20X when you have tens GB of data per OSD. So you can always see very bad sequential write performance (~200MB/s for a 12SSD setup), we can share more details on the performance meeting.
To this end, key-value backend with LevelDB is not useable for RBD usage, but maybe workable(not tested) in the LOSF cases ( tons of small objects stored via rados , k-v backend can prevent the FS metadata become the bottleneck)
From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Haomai Wang
Sent: Monday, December 1, 2014 9:48 PM
To: Satoru Funai
Cc: ceph-users@xxxxxxxx
Subject: Re: LevelDB support status is still experimental on Giant?
Yeah, mainly used by test env.
On Mon, Dec 1, 2014 at 6:29 PM, Satoru Funai <satoru.funai@xxxxxxxxx> wrote:
Hi guys,
I'm interested in to use key/value store as a backend of Ceph OSD.
When firefly release, LevelDB support is mentioned as experimental,
is it same status on Giant release?
Regards,
Satoru Funai
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Best Regards,
Wheat
Best Regards,
Wheat
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