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Message-ID: <7601f762-3449-4e66-9634-6f40afdc9b8f@exa.co.za>
Date: Wed, 18 Feb 2026 01:42:25 +0200
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Subject: Re: Postgres IO sweet spot
To: pgsql-performance@lists.postgresql.org
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 <CAKAnmmKXs4vpUt-3ML2H4rE4+3MEpHqG-rJVqvLqyaW0rfs3Jg@mail.gmail.com>
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From: Riaan Stander <rstander@exa.co.za>
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> That's an expensive way to provide some HA. What's the business 
> requirement? How does that tie into Postgres? Might be able to do it 
> in other ways.
We used to run a SAN shared between our host servers, but this was 
replaced with Storage Spaces. I think they don't trust Postgres native 
HA capabilities and want some hardware guarantee.

> Yikes! Yes, SSD would be a big win. It's orders of magnitude faster, 
> and just removes so many problems.
I assume it will help, but I fear however that the overhead with a 3 way 
mirror is not going to be solved with just adding SSD. I'm trying to get 
them to rather deploy direct attached NVME/SSD to each Host and then use 
PG HA from there.

> Sorry, I have no numbers to provide you there, but I cannot imagine 
> any amount of tuning is going to be as big a win as going to SSD.
It does take a lot of convincing and arguing though, so concrete number 
help get the point across.

Thanks for the response

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    <blockquote type="cite"
cite="mid:CAKAnmmKXs4vpUt-3ML2H4rE4+3MEpHqG-rJVqvLqyaW0rfs3Jg@mail.gmail.com">
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          <div>That's an expensive way to provide some HA. What's the
            business requirement? How does that tie into Postgres? Might
            be able to do it in other ways.</div>
        </div>
      </div>
    </blockquote>
    We used to run a SAN shared between our host servers, but this was
    replaced with Storage Spaces. I think they don't trust Postgres
    native HA capabilities and want some hardware guarantee.<br>
    <br>
    <blockquote type="cite"
cite="mid:CAKAnmmKXs4vpUt-3ML2H4rE4+3MEpHqG-rJVqvLqyaW0rfs3Jg@mail.gmail.com">
      <div dir="ltr">
        <div class="gmail_quote gmail_quote_container">
          <div>Yikes! Yes, SSD would be a big win. It's orders of
            magnitude faster, and just removes so many problems.</div>
        </div>
      </div>
    </blockquote>
    I assume it will help, but I fear however that the overhead with a 3
    way mirror is not going to be solved with just adding SSD. I'm
    trying to get them to rather deploy direct attached NVME/SSD to each
    Host and then use PG HA from there.<br>
    <br>
    <blockquote type="cite"
cite="mid:CAKAnmmKXs4vpUt-3ML2H4rE4+3MEpHqG-rJVqvLqyaW0rfs3Jg@mail.gmail.com">
      <div dir="ltr">
        <div class="gmail_quote gmail_quote_container">
          <div>Sorry, I have no numbers to provide you there, but I
            cannot imagine any amount of tuning is going to be as big a
            win as going to SSD.</div>
        </div>
      </div>
    </blockquote>
    It does take a lot of convincing and arguing though, so concrete
    number help get the point across.<br>
    <br>
    Thanks for the response<br>
    <br>
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