On Wed, Apr 09, 2008 at 10:23:07AM +1000, Damian McGuckin
wrote:
> On Mon, 7 Apr 2008, Josef Grosch wrote:
>
> > I really can't answer your question. We tried the
LSI controller and had
> > a couple of problems. I think this was one of
them. We have settled on
> > the Adaptec 3805 which is an 8 port controller. We
are very happy with
> > this controller. It's fast, stable and well
supported in FreeBSD.
>
> With this, if you want to use it JBOD, don't you have
to create fake RAID
> volumes on each drive. Initially this is
>
> Drive0 Volume0
> Drive1 Volume1
>
> etc. Does FreeBSD use the Volume numbers at all when
assigning drive IDs
>
> /dev/da0
> /dev/da1
> ....
> /dev/daN
>
> or does it work purely from the slot position?
>
> Many Thanks - Damian
We have not used JBOD as such. We mostly use RAID 0, 1, 5,
10. I fooled
around with JBOD with each disk being stand alone. The
controller presented
each disk as a separate device ie. da0, da1 ... daN. So, no,
you do not
have to RAID a disk if you want stand alone. I did this when
testing ZFS on
7.0.
The controller labels the disk with something the controller
sees but the
OS does not. I know this because I moved, these are hot swap
units, a disk
from one slot to another and the controller told me that the
label did not
match the slot number. I assume the controller relabeled the
disk or more
correctly updated it's internal map because it never
complained again.
That being said, the controller presents the OS with a
device and hides the
details from the OS. I have had a number of situations where
I have 6
drives in a RAID 10 and had to move disks around from their
original
slot. The controller bitched once but the OS, FreeBSD 6.2,
6.3, 7.0 saw the
RAID as one disk with one device. It never knew that the
disks had been
moved around.
We at Juniper have a long history of using Adaptec
controllers. I have
about 200 servers using the 3805 and, except for outdated
firmeware, have
never had a problem with them. I think if you start using
the 3805 it will
be one less thing to think about and you can go back to
putting out all the
other fires you are fighting 
Josef
--
FreeBSD 6.3 |
Josef Grosch | You can't expect to wield supreme
executive power
jgrosch juniper.net | just 'cause some watery tart threw a
sword at you!
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