Fresh install on gmirror'ed disks?

Volker volker at
Tue Mar 7 11:55:33 UTC 2006

> On Friday 03 March 2006 23:45, Mark Kirkwood wrote:
>> >
>> > I would certainly see the installer handling software RAID as a
>> > considerable benefit.
>> >
>> >  From what I've seen on the net, to install and boot off RAIDed system
>> > disks is quite fiddly (maybe gmirror is the exception here, as I've
>> > mainly been looking at striping).
>> >
>> > Cheers
>> >
>> > Mark
> geom changed this complications definitely, using gmirror or gstripe commands 
> is easy as copying a file. Probably one of the most important things that 
> with vinum as example it was not possible to mirror a root partition but 
> since gmirror places the metadata different we can have now a mirrored and 
> bootable root partition. Striping with ccd and vinum or mirroring was 
> certainly a pain even if it worked then stable and reliable. So in comparism 
> the easy use of geom is great and the people which developed geom did a 
> really fantastic job.
> João


I do agree that gmirror is not that bad and not that difficult. But
take a look at how to setup a fresh system using gmirror (slice by
slice mirroring):

- install a complete system to a fresh disc
- create the (well sized) slices on a 2nd disc (not that easy)
- create the gmirror set on disc 2
- bring gmirror up
- copy all filesystems over to the gmirror set
- reboot
- create exactly sized slices on disc 1
- insert everything into the gmirror set

Using that procedure you're going to copy each installed file three
times (install, copy to mirror, sync mirror). That's a waste of time
compared to a solution where the installer would be able to install
directly into a mirror.

When using disc based gmirror (instead of per slice gmirror) the
procedure is a bit easier, but similar.

If one could create a gmirror set before installing the base system
and tell the installer to install into gmX instead of adX/daX, the
whole procedure would be much easier and would take less time.

I've had to setup a handful of fresh systems over the last months
and it was a pain to manually setup gmirror on each fresh system.



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