NFS reads vs. writes

[Adam Vande More]

On Mon, Jan 4, 2016 at 9:06 PM, Paul Kraus <paul at kraus-haus.org> wrote:

> I have a file server that I am going through the task of optimizing for
> NFS traffic (to store VM images). My first attempt, because I knew about
> the need for an SSD based SLOG for the ZIL was using a pair of Intel 535
> series SSD’s. The performance with the SLOG/ZIL on the SSD was _worse_.
> Turns out that those SSD’s have poor small block (8 KB) random write
> performance (not well advertised). So I asked for advice for choosing a
> _fast_ SSD on the OpenZFS list and had a number of people recommend the
> Intel DC-Sxxxx series of SSDs.
>
> Based on the very thorough data sheets, I am going with a pair of DC-S3710
> 200 GB SSDs. Once I get them in and configured I’ll post results.
>
> Note that my zpool consists of 5 top level vdevs each made up of a 3-way
> mirror. So I am striping writes across 5 columns. I am using 500 GB WD RE
> series drives leaving the ZIL on the primary vdevs was _faster_ than adding
> the consumer SSD as SLOG for NFS writes


Something like zeusram or ddrdrive is probably going to yield the most
preformant solution for zfs sync writes.



-- 
Adam