Re: suggestions for postgresql setup on Dell 2950 , PERC6i controller - Mailing list pgsql-performance

From Gary Doades
Subject Re: suggestions for postgresql setup on Dell 2950 , PERC6i controller
Date
Msg-id 4989F99C.6090803@gpdnet.co.uk
Whole thread Raw
In response to suggestions for postgresql setup on Dell 2950 , PERC6i controller  (Rajesh Kumar Mallah <mallah.rajesh@gmail.com>)
List pgsql-performance
Rajesh Kumar Mallah wrote:
> Hi,
>
> I am going to get a Dell 2950 with PERC6i with
> 8 * 73 15K SAS drives +
> 300 GB EMC SATA SAN STORAGE,
>
> I seek suggestions from users sharing their experience with
> similar hardware if any. I have following specific concerns.
>
> 1. On list i read  that RAID10 function in PERC5 is not really
>    striping but spanning and does not give performance boost
>    is it still true in case of PERC6i ?

It's long been our policy to buy Dell servers and I agree with most
people here that the performance of the PERCs (5 and earlier) have been
generally pretty poor

However, they seem to have listened and got it right, or at least a lot
better, with the PERC6.

I have recently installed Ubuntu server on 2 Dell 2950s with 8GB RAM and
six 2.5 inch 15K rpm SAS disks in a single RAID10.

I only got chance to run bonnie++ on them a few times, but I was
consistently getting around 200MB/sec for both sequential read and write
(16GB file).

Similar setup with the older Dell 2850 (PERC5, 6 x 15K rpm 3.5 inch
SCSI) gave only around 120GB/sec whatever I did.

Hope this helps.

Cheers,
Gary.

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