Message-ID: <4613F7DC.40404@tweakers.net>
Date: Wed, 04 Apr 2007 21:09:16 +0200
From: Arjen van der Meijden <acmmailing@tweakers.net>
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To: "jason@ohloh.net" <jason@ohloh.net>
CC: pgsql-performance@postgresql.org
Subject: Re: SCSI vs SATA
References: <9C0858F5-0A48-4AF9-80FF-E4BA14F0F965@ohloh.net>
In-Reply-To: <9C0858F5-0A48-4AF9-80FF-E4BA14F0F965@ohloh.net>
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On 4-4-2007 0:13 jason@ohloh.net wrote:
> We need to upgrade a postgres server. I'm not tied to these specific 
> alternatives, but I'm curious to get feedback on their general qualities.
> 
> SCSI
>   dual xeon 5120, 8GB ECC
>   8*73GB SCSI 15k drives (PERC 5/i)
>   (dell poweredge 2900)

This is a SAS set-up, not SCSI. So the cabling, if an issue at all, is 
in SAS' favour rather than SATA's. Normally you don't have to worry 
about that in a hot-swap chassis anyway.

> SATA
>   dual opteron 275, 8GB ECC
>   24*320GB SATA II 7.2k drives (2*12way 3ware cards)
>   (generic vendor)
> 
> Both boxes are about $8k running ubuntu. We're planning to setup with 
> raid10. Our main requirement is highest TPS (focused on a lot of INSERTS).
> 
> Question: will 8*15k SCSI drives outperform 24*7K SATA II drives?

I'm not sure this is an entirely fair question given the fact that the 
systems aren't easily comparable. They are likely not the same build 
quality or have the same kind of support, they occupy different amounts 
of space (2U vs probably at least 4U or 5U) and there will probably a be 
difference in energy consumption in favour of the first solution.
If you don't care about such things, it may actually be possible to 
build a similar set-up as your SATA-system with 12 or 16 15k rpm SAS 
disks or 10k WD Raptor disks. For the sata-solution you can also 
consider a 24-port Areca card.


Best regards,

Arjen