Re: Bad iostat numbers

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От
Alex Turner
Тема
Re: Bad iostat numbers
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Msg-id
33c6269f0612050457s4a8eb0eas662d7a50fb5dfa89@mail.gmail.com
Ответ на
Re: Bad iostat numbers (Michael Stone)
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Дерево обсуждения
Bad iostat numbers "Carlos H. Reimer" <carlos.reimer@opendb.com.br>
Re: Bad iostat numbers Mark Kirkwood <markir@paradise.net.nz>
RES: Bad iostat numbers "Carlos H. Reimer" <carlos.reimer@opendb.com.br>
Re: Bad iostat numbers David Boreham <david_list@boreham.org>
Re: Bad iostat numbers Mark Kirkwood <markir@paradise.net.nz>
RES: Bad iostat numbers "Carlos H. Reimer" <carlos.reimer@opendb.com.br>
Re: RES: Bad iostat numbers David Boreham <david_list@boreham.org>
Re: Bad iostat numbers Greg Smith <gsmith@gregsmith.com>
Re: Bad iostat numbers "Alex Turner" <armtuk@gmail.com>
Re: Bad iostat numbers Scott Marlowe <smarlowe@g2switchworks.com>
Re: Bad iostat numbers Scott Marlowe <smarlowe@g2switchworks.com>
Re: Bad iostat numbers "Alex Turner" <armtuk@gmail.com>
Re: Bad iostat numbers Scott Marlowe <smarlowe@g2switchworks.com>
Re: Bad iostat numbers Michael Stone <mstone+postgres@mathom.us>
Re: Bad iostat numbers Scott Marlowe <smarlowe@g2switchworks.com>
Re: Bad iostat numbers "Alex Turner" <armtuk@gmail.com>
Re: Bad iostat numbers Michael Stone <mstone+postgres@mathom.us>
Re: Bad iostat numbers Greg Smith <gsmith@gregsmith.com>
Re: Bad iostat numbers "Alex Turner" <armtuk@gmail.com>
Re: Bad iostat numbers Michael Stone <mstone+postgres@mathom.us>
Re: Bad iostat numbers "Alex Turner" <armtuk@gmail.com>
Re: Bad iostat numbers Michael Stone <mstone+postgres@mathom.us>
Re: Bad iostat numbers "Craig A. James" <cjames@modgraph-usa.com>
Re: Bad iostat numbers Greg Smith <gsmith@gregsmith.com>
Re: Bad iostat numbers Steve Atkins <steve@blighty.com>
The problem I see with software raid is the issue of a battery backed unit: If the computer loses power, then the 'cache' which is held in system memory, goes away, and fubars your RAID.

Alex

On 12/5/06, Michael Stone <mstone+postgres@mathom.us> wrote:
On Tue, Dec 05, 2006 at 01:21:38AM -0500, Alex Turner wrote:
>My other and most important point is that I can't find any solid
>recommendations for a SCSI card that can perform optimally in Linux or
>*BSD.  Off by a factor of 3x is pretty sad IMHO. (and yes, we know the
>Adaptec cards suck worse, that doesn't bring us to a _good_ card).

This gets back to my point about terminology. As a SCSI HBA the Adaptec
is decent: I can sustain about 300MB/s off a single channel of the
39320A using an external RAID controller. As a RAID controller I can't
even imagine using the Adaptec; I'm fairly certain they put that
"functionality" on there just so they could charge more for the card. It
may be that there's not much market for on-board SCSI RAID controllers;
between SATA on the low end and SAS & FC on the high end, there isn't a
whole lotta space left for SCSI. I definitely don't think much
R&D is going into SCSI controllers any more, compared to other solutions
like SATA or SAS RAID (the 39320 hasn't change in at least 3 years,
IIRC). Anyway, since the Adaptec part is a decent SCSI controller and a
lousy RAID controller, have you tried just using software RAID?

Mike Stone

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