[OpenIndiana-discuss] Recommendations for fast storage

[Jay Heyl]

On Mon, Apr 15, 2013 at 5:00 AM, Edward Ned Harvey (openindiana) <
openindiana at nedharvey.com> wrote:

>
> So I'm just assuming you're going to build a pool out of SSD's, mirrored,
> perhaps even 3-way mirrors.  No cache/log devices.  All the ram you can fit
> into the system.


What would be the logic behind mirrored SSD arrays? With spinning platters
the mirrors improve performance by allowing the fastest of the mirrors to
respond to a particular command to be the one that defines throughput. With
SSDs, they all should respond in basically the same time. There is no
latency due to head movement or waiting for the proper spot on the disc to
rotate under the heads. The improvement in read performance seen in
mirrored spinning platters should not be present with SSDs. Admittedly,
this is from a purely theoretical perspective. I've never assembled an SSD
array to compare mirrored vs RAID-Zx performance. I'm curious if you're
aware of something I'm overlooking.