Re: Latest advice on SSD?

[Matthew Hall <mhall@xxxxxxxxxxxxxxx>]

The most critical bit of advice I've found is setting this preference:

https://amplitude.engineering/how-a-single-postgresql-config-change-improved-slow-query-performance-by-50x-85593b8991b0

I'm using 4 512GB Samsung 850 EVOs in a hardware RAID 10 on a 1U server with about 144 GB RAM and 8 Xeon cores. I usually burn up CPU more than I burn up disks or RAM as compared to using magnetic where I had horrible IO wait percentages, so it seems to be performing quite well so far. 

Matthew Hall

On Apr 9, 2018, at 7:36 PM, Craig James <cjames@xxxxxxxxxxxxxx> 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:

  8 core (Intel)

  48GB memory

  12-drive 7200 RPM 500GB

     RAID1 (2 disks, OS and WAL log)

     RAID10 (8 disks, postgres data dir)

     2 spares

  Ubuntu 16.04

  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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Craig A. James

Chief Technology Officer

eMolecules, Inc.

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