SUMMARY: Using raidctl to mirror boot disk after installation.

From: Rob McMahon <>
Date: Tue May 17 2011 - 04:59:01 EDT
On 16/05/2011 16:52, Rob McMahon wrote:
> We have a Sun Fire X4100 M2, which has just lost a disk.  This was all
> mirrored using SVM, but getting the system back running on one disk
> proved to be more of a pain than it should have been, and we'd like to
> use the hardware RAID controller when we replace the broken disk.  The
> system is now using normal raw partitions as a result of the problems
> bringing it back.  Now I'd like to think I could just do
> raidctl -c c3t2d0 c3t3d0
> and be done, but there are dire warnings that you have to 1) do this
> from remote / DVD media (which is not a problem), and 2) re-install the
> OS afterwards, which is.
> It's a long time since I've done this, but I remember the disk geometry
> changes.  If we just lose two or three cylinders off the end of the
> disk, this wouldn't be a problem, since the last 3 cylinders are just a
> metadb, which I could destroy.
> Has anyone got any advice ?  This is quite urgent, because if I can't
> find an answer quickly, I'll just have to SVM it up again to be safe.
> Cheers,
> Rob
Almost unanimously people have said stick with SVM.  The glaring error I 
made, which I realised myself as I was digging the machine out of its 
hole, was to miss out adding the following to /etc/system

set md:mirrored_root_flag=1

Matt Morris pointed this out.  Thanks.

One of the partitions (with scratch data - quarantined virus mails) was 
created as RAID 0 for performance rather than RAID 1 for redundancy, and 
this was obviously an issue too.  We live and learn.  Excerpts from the 
responses (thanks everyone):

Chris Hoogendyk, Adrian Koester, and Matthew Stier all basically said 
you do have to re-partition and re-install.
Anthony D'Atri said forget HW RAID and go ZFS.  It's a good point, but 
these machines were installed while ZFS was still young, and there was 
no ZFS boot.  Another re-install.
In addition to the /etc/system addition, Matt Morris said "And hardware 
RAID is AWFUL, IMO. SVM is tried and true, easy to manage, and easy to 
get drive status online. I've just never had good experiences with HW 
RAID..."  A sentiment I agree with, but people around me were asking why 
I didn't go for HW RAID.

I'm sticking with SVM.  Thanks again for all your input.


E-Mail:		PHONE:  +44 24 7652 3037
Rob McMahon, IT Services, Warwick University, Coventry, CV4 7AL, England
sunmanagers mailing list
Received on Tue May 17 05:00:06 2011

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