# Installing 9.1 and migrating a gmirror



## megaplaychop (Feb 18, 2013)

Hi there,

I have a question regarding an install of 9.1 that I plan to do on my little computer that I use as a NAS. Currently it runs 8.1 but there are a bunch of broken packages (due to my fiddling around) on it and I figured I'd switch to 9.1 by doing a clean install rather than an upgrade.

My setup is as follows:
- ad6 is my system/boot HDD, contains the install basically, including /home
- ad8 and ad10 are 2 1TB (same brand etc.) HDD that are currently configured with gmirror as mirror/gm0 and mounted as /opt

What I want to do is scrap stuff on ad6 (minus some config files and home dirs which I'll save on a usb key), install 9.1, and just use the mirror as it is. That is, I don't want to have to rebuild it nor do I want to lose the data on it (I can't backup 1TB on DVD and don't have access to a portable HD to do so). Please note that it's a small computer so I don't have enough RAM to run ZFS (I jave 512 mb of RAM).

Originally my idea was to:
- Unplug the mirrored HDDs
- Install 9.1, configure base stuff
- Plug the mirrored HDDs back in, reboot and be done with it once I add the mirror back to fstab

However, I'm reading the mirroring HOW-TO and there's new stuff about gpart and so on which I don't remember having to deal with when I setup the 8.1 more than a year ago.

So my question is whether my original idea makes sense or not. Can I just do it this way? Or is there something I have to do using gmirror commands to tell freebsd 9.1 that I have a mirror that it did not know about upon a reboot? Or should I just say screw it, plug only one drive, follow the HOW-TO and do a new mirror construction by plugging the new drive?

I figured this should be easy since it's not a bootable mirror but I'm anxious at losing my data or having an irrecuperable mirror 

Many thanks in advance,

Greg


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## wblock@ (Feb 18, 2013)

That's a reasonable procedure.  What "mirroring How-To" are you reading?  The Handbook has the correct procedure, both for creating a new mirror and adding a new drive to an existing one: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/geom-mirror.html.

If the existing mirror was set up correctly, it should work without problems on 9.1.  Even if it followed the old instructions that made a not-quite-right mirror, the safety check on 9.x can be disabled to still use it.  See http://www.freebsd.org/releases/9.0R/relnotes-detailed.html#AEN1277.


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## megaplaychop (Feb 19, 2013)

Hi,

Thanks for the help. That is the handbook section I was looking at. Back in 8.1 I believe it was just a matter of creating the mirror, creating the slice and mounting. Although I may have forgotten since... 

Anyway I just didn't remember playing with gpart at that time. I guess I could go with disabling the check until I upgrade to 2TB HDD sometime in the future 

My case is slightly different from those shown in the handbook and I just wasn't sure how to proceed. I basically want to migrate a mirror onto a new install (could be a new machine for example). I just finished downloading the ISO, I guess I'll figure all this out very soon .

Regards,

Greg

P.S: I will try to find a way to back that up anyway I think since I'm no expert in this


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