Re: Making the most of memory? - Mailing list pgsql-performance

From Florian Weimer
Subject Re: Making the most of memory?
Date
Msg-id 824pd28gim.fsf@mid.bfk.de
Whole thread Raw
In response to Re: Making the most of memory?  (Chris Browne <cbbrowne@acm.org>)
List pgsql-performance
* Chris Browne:

>> A dedicated RAID controller with battery-backed cache of ssuficient
>> size and two mirrored disks should not perform that bad, and has the
>> advantage of easy availability.
>
> That won't provide as "souped up" performance as "WAL on SSD," and
> it's from technical people wishing for things that some of those
> things actually emerge...

For WAL (I/O which is mostly sequential), the proposed approach isn't
that bad.  You can easily get more than 15,000 write transactions per
second, with a single thread.  Good luck finding a SSD NAS with a
60 usec round-trip time. 8->

Something which directly speaks SATA or PCI might offer comparable
performance, but SSD alone isn't sufficient.

--
Florian Weimer                <fweimer@bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
Kriegsstraße 100              tel: +49-721-96201-1
D-76133 Karlsruhe             fax: +49-721-96201-99

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