On Mon, May 26, 2014 at 5:23 PM, Wido den Hollander <wido@xxxxxxxx> wrote: > On 05/26/2014 06:55 AM, Haomai Wang wrote: >> >> On Mon, May 26, 2014 at 9:46 AM, Guang Yang <yguang11@xxxxxxxxxxx> wrote: >>> >>> Hello Haomai, >>> We are evaluating the key-value store backend which comes along with >>> Firefly release (thanks for implementing it in Ceph), it is very promising >>> for a couple of our use cases, after going through the related code change, >>> I have a couple of questions which needs your help: >>> 1. One observation is that, for object larger than 1KB, it will be >>> striped to multiple chunks (k-v in the leveldb table), with one strip as 1KB >>> size. Is there any particular reason we choose 1KB as the strip size (and I >>> didn’t find a configuration to tune this value)? >> >> >> 1KB is not a serious value, this value can be configured in the near >> future. >> > > So that is currently hardcoded? I can't find any reference to it in > config_opts.h Yes > > >>> >>> 2. This is properly a leveldb question, do we expect performance >>> degradation as the leveldb instance keeps increasing (e.g. several TB)? >> >> >> Ceph OSD is expected to own a physical disk, normally is several >> TB(1-4TB). LevelDB can take it easy. Especially we use it to store >> large value(compared to normal application usage). >> > > With a large value you mean something like 4MB? The regular strip-size for > RBD, CephFS and such? Not 4MB, it should be 4KB matching the default page size in kernel. Or 4MB for radosgw goal. I want to match the operation "set_alloc_size" and make it better for workload. > >>> >>> Thanks, >>> Guang >> >> >> >> > > > -- > Wido den Hollander > 42on B.V. > > Phone: +31 (0)20 700 9902 > Skype: contact42on -- Best Regards, Wheat -- 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
