[OpenIndiana-discuss] Very slow write performance on a 3 disk raidz1-0 zpool

[Sašo Kiselkov]

On 08/24/2012 12:25 PM, Julius Roberts wrote:
> On 24 August 2012 15:03, Robbie Crash <sardonic.smiles at gmail.com> wrote:
>> Are you using compression or dedup on the FS?
> 
> We're getting about 1.5x dedup

P.S. 1.5x for dedup is essentially worthless for its cost in RAM and
performance. You'll be much better off with compression only, that alone
can give you anywhere from 1.5x to 2.0x using an average compressible
dataset at a much, much lower cost to performance (on that machine you
have there lzjb should be able to give you well in excess of 100-150MB/s
write performance). See https://www.illumos.org/issues/3035 for a few
comparative compression benchmarks I did when integrating LZ4
compression into Illumos.

--
Saso