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Re: [PERFORM] Very poor read performance, query independent - Mailing list pgsql-performance

From Charles Nadeau
Subject Re: [PERFORM] Very poor read performance, query independent
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Msg-id CADFyZw579_W96dD_beduHeCFomVg1Xe8P+Kpi6jq3Z8+GsYVjw@mail.gmail.com
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In response to Re: [PERFORM] Very poor read performance, query independent  (Mark Kirkwood <mark.kirkwood@catalyst.net.nz>)
Responses Re: [PERFORM] Very poor read performance, query independent  (Mark Kirkwood <mark.kirkwood@catalyst.net.nz>)
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Mark,

I received yesterday a second server having 16 drives bays. Just for a quick trial, I used 2 old 60GB SSD (a Kingston V300 and a ADATA SP900) to build a RAID0. To my surprise, my very pecky RAID controller (HP P410i) recognised them without a fuss (although as SATAII drives at 3Gb/s. A quick fio benchmark gives me 22000 random 4k read IOPS, more than my 5 146GB 10k SAS disks in RAID0). I moved my most frequently used index to this array and will try to do some benchmarks.
Knowing that SSDs based on SandForce-2281 controller are recognised by my server, I may buy a pair of bigger/newer ones to put my tables on.

Thanks!

Charles

On Sat, Jul 15, 2017 at 1:57 AM, Mark Kirkwood <mark.kirkwood@catalyst.net.nz> wrote:
Thinking about this a bit more - if somewhat more blazing performance is needed, then this could be achieved via losing the RAID card and spinning disks altogether and buying 1 of the NVME or SATA solid state products: e.g

- Samsung 960 Pro or Evo 2 TB (approx 1 or 2 GB/s seq scan speeds and 200K IOPS)

- Intel S3610 or similar 1.2 TB (500 MB/s seq scan and 30K IOPS)


The Samsung needs an M.2 port on the mobo (but most should have 'em - and if not PCIe X4 adapter cards are quite cheap). The Intel is a bit more expensive compared to the Samsung, and is slower but has a longer lifetime. However for your workload the Sammy is probably fine.

regards

Mark

On 15/07/17 11:09, Mark Kirkwood wrote:
Ah yes - that seems more sensible (but still slower than I would expect for 5 disks RAID 0).



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Charles Nadeau Ph.D.
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