From: Scott Marlowe <scott.marlowe@gmail.com>
To: Sean Davis <sdavis2@mail.nih.gov>
Cc: pgsql-performance@postgresql.org
Subject: Re: [OT] RAID controllers blocking one another?
Date: Thu, 17 Jan 2008 15:07:02 -0600
Message-ID: <dcc563d10801171307p4869b0ayc27c3433c19455ba@mail.gmail.com> (raw)
In-Reply-To: <264855a00801171217m4e6211e6y5f4d0e12ce86db5c@mail.gmail.com>
References: <264855a00801171217m4e6211e6y5f4d0e12ce86db5c@mail.gmail.com>
On Jan 17, 2008 2:17 PM, Sean Davis <sdavis2@mail.nih.gov> wrote:
> We have a machine that serves as a fileserver and a database server. Our
> server hosts a raid array of 40 disk drives, attached to two3-ware cards,
> one 9640SE-24 and one 9640SE-16. We have noticed that activity on one
> controller blocks access on the second controller, not only for disk-IO but
> also the command line tools which become unresponsive for the inactive
> controller. The controllers are sitting in adjacent PCI-express slots on a
> machine with dual-dual AMD and 16GB of RAM. Has anyone else noticed issues
> like this? Throughput for either controller is a pretty respectable
> 150-200MB/s writing and somewhat faster for reading, but the "blocking" is
> problematic, as the machine is serving multiple purposes.
>
> I know this is off-topic, but I know lots of folks here deal with very large
> disk arrays; it is hard to get real-world input on machines such as these.
Sounds like they're sharing something they shouldn't be. I'm not real
familiar with PCI-express. Aren't those the ones that use up to 16
channels for I/O? Can you divide it to 8 and 8 for each PCI-express
slot in the BIOS maybe, or something like that?
Just a SWAG.
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To: pgsql-performance@postgresql.org
Cc: scott.marlowe@gmail.com, sdavis2@mail.nih.gov
Subject: Re: [OT] RAID controllers blocking one another?
In-Reply-To: <dcc563d10801171307p4869b0ayc27c3433c19455ba@mail.gmail.com>
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