booting off a ZFS pool consisting of multiple striped mirror vdevs

[Matt Reimer]

On Thu, Feb 18, 2010 at 4:36 PM, Dan Naumov <dan.naumov at gmail.com> wrote:

>
> A stripe of 3-way mirrors, whoa. Out of curiosity, what is the system
> used for? I am not doubting that there exist some uses/workloads for a
> system that uses 6 disks with 2 disks worth of usable space, but
> that's a bit of an unusual configuration. What are your system/disc
> specs and what kind of performance are you seeing from the pool?
>

It's for a reasonably busy webserver hosting a few hundred domains, which
tends to be somewhat seek-intensive.

For this pool we had two main criteria: speed and double-disk redundancy. A
stripe of three two-way mirrors would only give us single-disk redundancy in
the worst case (i.e. losing both disks in one of the mirrors), so we went
with two three-way mirrors instead. Even though we're only getting the
capacity of two disks worth of space, we'll still have 6x the capacity of
the array it's replacing.

A simple-minded dd test gives me ~180MB/s writing a single long file, and
400-500MB/s reading.

Matt