Hi, On 17/03/2015 08:27, Xinze Chi wrote: > hi, loic: > > I have an idea which could reduce read latency and bandwidth for ec pool. > > But, I don't know whether it is feasible. > > Such as ec pool stripe_width = 16384 = 4 * 4096, K = 4, M =2 > > So ceph will partition the total of 16384 bytes to 4 data chunk, > and encoding 2 parity chunk > > shard_0 include 0 - (4096-1) in original data; > shard_1 include 4096 - (4096*2 - 1) in original data; > shard_2 include 4096*2 - (4096 * 3 -1) in original data; > shard_3 include 4096*3 - (4096 * 4 - 1) in original data > shard_4 include parity chunk > shard_5 include parity chunk > > Now if client read (offset 0, len 4096) from object, it should > read 4 shard (from 0-3) and decode all this 4 chunk. > > But, this example, maybe we can compute the destination shard > based on ec pool config ,read offset and read len , we only read > > shard_0 and return it to client, because shard_0 has include all data > as client need. That optimization makes sense to me. I guess you're interested in having small objects in the pool and only read a few bytes at a time ? Cheers > > Wait for your comment. > > Thanks. > -- Loïc Dachary, Artisan Logiciel Libre
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