I'm in the planing stages of a rather larger ZFS system to house
approximately 1 PB of data.
I have only one system with SSDs for L2ARC and ZIL, The ZIL seems to be
the bottle neck for large bursts of data being written. I can't confirm
this for sure, but the when throwing enough data at my storage pool and the
write latency starts rising, the ZIL write speed hangs close the max
sustained throughput I've measured on the SSD (~200 MB/s).
The pool when empty w/o L2ARC or ZIL it was tested with Bonnie++ and showed
~1300MB/s serial read and ~800MB/s serial write speed.
How can I determine for sure that my ZIL is my bottleneck? If it is the
bottleneck, is it possible to keep adding mirrored pairs of SSDs to the ZIL
to make it faster? Or should I be looking for a DDR drive, ZeusRAM, etc.
Thanks for any input,
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