Lines Matching full:parity

2 Partial Parity Log
5 Partial Parity Log (PPL) is a feature available for RAID5 arrays. The issue
6 addressed by PPL is that after a dirty shutdown, parity of a particular stripe
8 in degraded state, there is no way to recalculate parity, because one of the
10 array or using it is as degraded - data calculated from parity for array blocks
15 Partial parity for a write operation is the XOR of stripe data chunks not
17 write hole. XORing partial parity with the modified chunks produces parity for
20 this stripe is missing, this updated parity can be used to recover its
26 When handling a write request PPL writes partial parity before new data and
27 parity are dispatched to disks. PPL is a distributed log - it is stored on
28 array member drives in the metadata area, on the parity drive of a particular
37 performed for this stripe (parity is not updated). So it is possible to have