[rescue] Imaging Solaris 2.5 without SCSI devices

Cody Swanson mailinglists at sysop.ca
Tue Dec 6 11:34:10 CST 2011

I have had good luck with a perl script that runs once a week and clones 
the primary disk to an identical secondary disk. Once the DD is complete 
it does an fsck of the freshly written disk and e-mails our team if 
there are any issues. The dd is done while the system is live, usually 
around 1am.

This method, while completely unorthodox has saved hours of reinstall 
and restore when a primary disk goes south. Simply power down, swap the 
disks and reboot. 99 percent of the time a dead disk results in a less 
than 15 minute outage. It's a nice insurance policy. If the secondary 
disk swap doesn't work then you're in for a traditional reload/restore. 
Of course no real user data lives on the primary disk, just the OS. All 
user data is either mounted via autofs or SAN luns.

On 12/6/2011 6:55 AM, Carl R. Friend wrote:
>    On Mon, 5 Dec 2011, Ian Finder wrote:
>> Mostly what I'm worried about is DDing a mounted, running, volume.
>> Is this something that should be attempted from single user mode or 
>> similar?
>> Namely worried about filesystem integrity and locks.
>    Doing the image from single-user mode is the second-best option,
> the very best being to boot from other media (e.g. CD/DVD) and do
> the image that way.  From a running system, the net result you'll
> get will resemble a crash on the (newly-booted) image; you'll need
> to do an fsck on the filesystems, and things that were in the process
> of getting flushed to disk may be corrupt -- this is why you want
> to quiesce the system as much as possible whilst you're taking
> the "dd" snapshot.
>    Another *very* good way to snapshot a drive is to attach it to
> another system that has the proper controllers and "dd" the image
> that way.  In this case, since there is no possibility of the
> system being imaged being active you wind up with a pristine copy.
>    Cheers!
> +------------------------------------------------+---------------------+
> | Carl Richard Friend (UNIX Sysadmin)            | West Boylston       |
> | Minicomputer Collector / Enthusiast            | Massachusetts, USA  |
> | mailto:crfriend at rcn.com                        +---------------------+
> | http://users.rcn.com/crfriend/museum           | ICBM: 42:22N 71:47W |
> +------------------------------------------------+---------------------+
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