Re: ASM vs Hardware RAID vs ASM + Hardware RAID

From: Greg Rahn <>
Date: Thu, 3 Dec 2009 15:49:06 -0800
Message-ID: <>

First, I would comment that attaching an external fibre channel array to this host is probably not worth it. You are on a 585 G2 box and the current HP models are G6 (Intel 5500 Nehalem) and will smoke that in terms of performance. Not knowing your exact space requirements, I'd blindly suggest a server like the Sun Fire X4275 or Sun Fire X4270 - each of these have fast and plentiful storage options. The X4275 (also used for the Exadata servers) has 12 x 600GB SAS2 15K RPM drives (~7,200GB raw space) and scan speeds of over 1500GB/s, all on internal storage. Not to mention that each of these servers are 2U and you have a 4U host already and probably at least another 4U of space for a storage array. (And you are also on an ancient version of Red Hat)

I generally would recommend to use internal hardware RAID if it exists - just make the stripe columns as wide as possible (1MB is ideal as that is the default ASM AU (allocation unit) size). Using ASM (internal) redundancy is most useful when you have multiple arrays that can only be mirrored array-to-array using external software mechanisms.

Hope that helps.

On Thu, Dec 3, 2009 at 1:54 PM, Ray Feighery <> wrote:
> List
> Red Hat 4.0 x86_64
> HP DL 585 G2
> Oracle EE
> Looking for experiences of using ASM vs Hardware RAID.
> Currently have a database running on internal filesystem disks (no
> ASM, just standard ext3).  The database is outgrowing the internal
> disks, so the next step is to attach an external array.
> Can anyone recommend a good strategy?
> Options under consideration:
> 1) Array with raw disks attached and ASM
> 2) Array with hardware raid and filesystem (no ASM)
> 3) Some combination of hardware raid and ASM
> Also we're looking at the HP range of storage (MSA and EVA). Any
> recommendations or warnings about those would be good too.
> The storage will be dedicated to the database and flash recovery area.

Received on Thu Dec 03 2009 - 17:49:06 CST

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