Questions about 3Ware 7506 controller

[Simon]

On Sat, 14 Feb 2004 13:12:46 -0500 (EST), Alvin Gunkel wrote:

>I'm running 4.7 Release on a colocated system without access to
>bios/console.  This system currently has a Highpoint RocketRaid 100
>controller driving four WD 60gb (WD600JB, 8mb cache) drives in a raid 0+1
>config.  I had a drive fail and the controller kept the system up and
>functioning, but something has prevented rebuild from occurring, even in
>the bios util after replacing the failed drive.  As this is a most
>inconvienent situation I'm considering replacing the raid controller with
>a 3Ware 7506-4LP controller so I have more control from the OS level.

Did you issue rebuild? did you do it right? it won't know what to do on its own.
This is where SAF-TE SCA backplane comes in handy, but is only available
for SCSI, afaik.

>My two questions are:
>
>-What driver/firmware should I use?  I have a 3Ware 6410 running in
>another 4.7 system and am able to use the 3DM utils out of ports to
>monitor it.  I don't know if those utils support the 7506.  3Ware has a
>beta driver and command line utils for the 7506 and FreeBSD 4.8.  Which
>way to go?

I have 7506 under 5.1-R and it seems to work fine. I'm using default
drivers/firmware. However, I had to apply a patch to the 3dm utility as it
wouldn't bind to the right port.

>-Raid 10 or 5?  Compared to the 0+1 I have now, 10 would be a nice
>improvement as loss of the one drive effectively took out two of my
>drives.  Raid 5 would give me an extra 60gb to use, but I don't have any
>idea what the performance differential would be.

RAID 10 is better than RAID 5 when it comes to writes, a lot better. If you
want to know more, read:
http://www.pcguide.com/ref/hdd/perf/raid/concepts/perf_ReadWrite.htm
By the way, if you don't do a lot of writes, go with RAID 5, if you have a need
to perform constant writes, go with RAID 10.

-Simon