Date: Sat, 31 Jan 1998 16:28:00 -0500 (EST) From: Brian Tao <taob@nbc.netcom.ca> To: Karl Denninger <karl@mcs.net> Cc: current@FreeBSD.ORG Subject: Re: RAID controllers - folks, check this thing out Message-ID: <Pine.GSO.3.95.980131161942.27817Z-100000@tor-adm1> In-Reply-To: <19980131144604.03410@mcs.net>
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On Sat, 31 Jan 1998, Karl Denninger wrote:
>
> CCD mounted async is NOT a fair comparison - not at all.
I note that in my message. Async mounts delay metainfo writes,
and the RAID controller delays all writes to disk via its cache. It
would be unfair to CCD, in that your chances of recovering a busy
async filesystem after a crash are nearly zero. The comparison is
useful when you consider that the CMD is almost able to keep up even
without asynchronous updates.
> Also, RAID 5 with other than 5 disks is sub-optimal, and some of those
> tests were run with fewer drives.
What is magic about having 5 drives? Obviously the more drives
you add, the better the performance. I limited both RAID units to
three drives to provide a more level comparison. These were done on
eval units, and I would have liked six or more drives.
--
Brian Tao (BT300, taob@netcom.ca)
"Though this be madness, yet there is method in't"
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