The idea is that MLC SSD isn't advised for ZIL.
SLC is a lot better because it can withstand writing to the diks 10x
beter than MLC SSDs.
The best solution however is a DRAM ZIL.
It has better sustained iops and will be much durable.
Suggested reading material:
Post by Jason J. W. Williams
Does anyone have experience using the OCZ MLC Deneva's for ZIL?
Alternately the OCZ Vertex 2 EX SLC?
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