Benchmarking Ceph erasure code plugins

The erasure code implementation in Ceph relies on the jerasure library. It is packaged into a plugin that is dynamically loaded by erasure coded pools.
The ceph_erasure_code_benchmark is implemented to help benchmark the competing erasure code plugins implementations and to find the best parameters for a given plugin. It shows the jerasure technique cauchy_good with a packet size of 3072 to be the most efficient on a Intel(R) Xeon(R) CPU E3-1245 V2 @ 3.40GHz when compiled with gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5). The test was done assuming each object is spread over six OSDs and two extra OSDs are used for parity ( K=6 and M=2 ).

  • Encoding: 4.2GB/s
  • Decoding: no processing necessary (because the code is systematic)
  • Recovering the loss of one OSD: 10GB/s
  • Recovering the loss of two OSD: 3.2GB/s

The processing is done on the primary OSDs and therefore distributed on the Ceph cluster. Encoding and decoding is an order of magnitude faster than the typical storage hardware throughput.
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