Re: RAM, the more the merrier?

Am 29. Juni 2017 16:19:41 MESZ schrieb Willy-Bas Loos <willybas(at)gmail(dot)com>:
>Hi,
>
>We have a postgresql database that is now 1.4TB in disksize and slowly
>growing.
>In the past, we've had (read) performance trouble with this database
>and
>the solution was to buy a server that can fit the db into memory. It
>had
>0.5 TB of RAM and at the time it could hold all of the data easily.
>Those servers are now old and the db has outgrown the RAM and we are
>doing
>more reads and writes too (but the problem has not yet returned).
>
>So i am looking into buying new servers. I'm thinking of equipping it
>with
>1TB of RAM and room to expand. So the database will not fit completely,
>but
>largely anyway. Also, if we can afford it, it will have SSDs instead of
>RAID10 SAS spindles.
>
>But I've read that there is some kind of maximum to the shared_buffers,
>where increasing it would actually decrease performance.
>Is 1TB of RAM, or even 2TB always a good thing?
>And is there anything special that I should look out for when
>configuring
>such a server?
>Or would it be much better to buy 2 smaller servers and tie them
>together
>somehow? (partitioning, replication, ...)

With current versions you can set shared buffers to, for instance, 40% of ram, no problem. Tune also the checkpointer.

Regards, Andreas.

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