Subject: Re: Latest advice on SSD?
To: pgsql-performance@lists.postgresql.org
References: 
 <CAFwQ8rcCSiD2jC1JXHEh4fjxjzP+M9gGnbBNHj_+rm=Ng2ea+A@mail.gmail.com>
From: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
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Message-ID: <25749ee2-40cf-b189-4b6c-dfcee5ebc4ad@catalyst.net.nz>
Date: Wed, 11 Apr 2018 10:56:44 +1200
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We have been using the Intel S3710 (or minor model variations thereof).
They have been great (consistent performance, power off safe and good
expected lifetime). Also 2 of them in RAID1 easily outperform a
reasonably large number of 10K spinners in RAID10.

Now you *can* still buy the S37xx series, but eventually I guess we'll
have to look at something more modern like the S45xx series. But I'm not
so keen on them (they use TLC NAND which may give less consistent
performance, plus they appear to have slightly lower expected lifetime).
I think there was a thread a year or more ago on this list specifically
about this very issue that might be worth searching for.

The TLC NAND seems like a big deal - most modern SSD are built using
it...they solve the high latency problem with SLC caches. So you get
brilliant performance until the cache is full, then it drops off a
cliff. Bigger/more expensive drives have bigger caches, so it is well
worth finding in depth reviews of the exact models you might wish to
evaluate!

regards
Mark

On 10/04/18 14:36, Craig James wrote:
> One of our four "big iron" (spinning disks) servers went belly up
> today. (Thanks, Postgres and pgbackrest! Easy recovery.) We're
> planning to move to a cloud service at the end of the year, so bad
> timing on this. We didn't want to buy any more hardware, but now it
> looks like we have to.
>
> I followed the discussions about SSD drives when they were first
> becoming mainstream; at that time, the Intel devices were king. Can
> anyone recommend what's a good SSD configuration these days? I don't
> think we want to buy a new server with spinning disks.
>
> We're replacing:
> =C2=A0 8 core (Intel)
> =C2=A0 48GB memory
> =C2=A0 12-drive 7200 RPM 500GB
> =C2=A0 =C2=A0 =C2=A0RAID1 (2 disks, OS and WAL log)
> =C2=A0 =C2=A0 =C2=A0RAID10 (8 disks, postgres data dir)
> =C2=A0 =C2=A0 =C2=A02 spares
> =C2=A0 Ubuntu 16.04
> =C2=A0 Postgres 9.6
>
> The current system peaks at about 7000 TPS from pgbench.
>
> Our system is a mix of non-transactional searching (customers) and
> transactional data loading (us).
>
> Thanks!
> Craig
>


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    <div class="moz-cite-prefix">We have been using the Intel S3710 (or
      minor model variations thereof). They have been great (consistent
      performance, power off safe and good expected lifetime). Also 2 of
      them in RAID1 easily outperform a reasonably large number of 10K
      spinners in RAID10.<br>
      <br>
      Now you *can* still buy the S37xx series, but eventually I guess
      we'll have to look at something more modern like the S45xx series.
      But I'm not so keen on them (they use TLC NAND which may give less
      consistent performance, plus they appear to have slightly lower
      expected lifetime). I think there was a thread a year or more ago
      on this list specifically about this very issue that might be
      worth searching for.<br>
      <br>
      The TLC NAND seems like a big deal - most modern SSD are built
      using it...they solve the high latency problem with SLC caches. So
      you get brilliant performance until the cache is full, then it
      drops off a cliff. Bigger/more expensive drives have bigger
      caches, so it is well worth finding in depth reviews of the exact
      models you might wish to evaluate!<br>
      <br>
      regards<br>
      Mark <br>
      <br>
      On 10/04/18 14:36, Craig James wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAFwQ8rcCSiD2jC1JXHEh4fjxjzP+M9gGnbBNHj_+rm=Ng2ea+A@mail.gmail.com">
      <div dir="ltr">One of our four "big iron" (spinning disks) servers
        went belly up today. (Thanks, Postgres and pgbackrest! Easy
        recovery.) We're planning to move to a cloud service at the end
        of the year, so bad timing on this. We didn't want to buy any
        more hardware, but now it looks like we have to.
        <div><br>
        </div>
        <div>I followed the discussions about SSD drives when they were
          first becoming mainstream; at that time, the Intel devices
          were king. Can anyone recommend what's a good SSD
          configuration these days? I don't think we want to buy a new
          server with spinning disks.</div>
        <div><br>
        </div>
        <div>We're replacing:</div>
        <div>  8 core (Intel)</div>
        <div>
          <div
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial"> 
            48GB memory</div>
            12-drive 7200 RPM 500GB</div>
        <div>     RAID1 (2 disks, OS and WAL log)</div>
        <div>     RAID10 (8 disks, postgres data dir)</div>
        <div>     2 spares</div>
        <div>  Ubuntu 16.04<br>
        </div>
        <div>  Postgres 9.6</div>
        <div><br>
        </div>
        <div>The current system peaks at about 7000 TPS from pgbench.</div>
        <div><br>
        </div>
        <div>Our system is a mix of non-transactional searching
          (customers) and transactional data loading (us).</div>
        <div><br>
        </div>
        <div>Thanks!</div>
        <div>Craig<br clear="all">
          <div><br>
          </div>
        </div>
      </div>
    </blockquote>
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