Re: SATA drives performance - Mailing list pgsql-performance

From Ognjen Blagojevic
Subject Re: SATA drives performance
Date
Msg-id 4B33D895.5020807@etf.bg.ac.yu
Whole thread Raw
In response to Re: SATA drives performance  (Richard Neill <rn214@cam.ac.uk>)
List pgsql-performance
Richard and others, thank you all for your answers.

My comments inline.

Richard Neill wrote:
 > 2. Also, for reads, the more RAM you have, the better (for caching). I'd
 > suspect that another 8GB of RAM is a better expenditure than a 2nd drive
 > in many cases.

The size of the RAM is already four time of the database size, so I
believe I won't get any more benefit if it is increased. The number of
simultaneous connections to the database is small -- around 5.

What I'm trying to do with the hard disk configuration is to increase
the write speed.


 > 3. RAID 0 is twice as unreliable as no raid. I'd recommend using RAID 1
 > intead. If you use the Linux software mdraid, remote admin is easy.

No, actually it is HP ML series server with HW RAID. I don't have too
much experience with it, but I believe that the remote administration
might be hard. And that was the main reason I was avoiding RAID 1.


 > 5. For a 2-disk setup, I think that main DB on one, with WAL on the
 > other will beat having everything on a single RAID0.
 >
 > 6. The WAL is relatively small: you might consider a (cheap) solid-state
 > disk for it.

These are exactly the thing I was also considering. -- but needed advice
from people who tried it already.

Regards,
Ognjen



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