Setting up gmirror

[Dino Vliet]

Wednesday, October 1, 2008 6:34 AM




From: 

"Andrew Falanga" <af300wsm at gmail.com>



To: 
"freebsd-questions at freebsd.org" <freebsd-questions at freebsd.org>


Hi,

I've just finished setting up a new web server, and if I get my DNS
stuff correct hopefully an e-mail server too, for my church.
Originally, the intention was to use RAID1 on the MOBO.  However, the
RAID controller on the MOBO consistently tried to make the SATA DVD
drive part of the RAID array and wouldn't boot the FreeBSD boot disk.
So, at the suggestion of another respondent here, I've decided to use
gmirror.

Now, it seems that gmirror is, perhaps, newer to FreeBSD than the
software RAID stuff in the Handbook.  That mentions ccd(4) and doesn't
make any mention of gmirror(8).  It seems like gmirror is rather easy
to work with, and more important, easy to recover from is hardware
fails.  In any event, I want to make sure I'm understanding the manual
page correctly because I don't have anything else to test this on
except the churches computer.  We have two Seagate 250gb SATA drives.
Identical drive models so their sizes are the same.  Is this the
command, from gmirror(8), the one I'll want to use?

     Create a mirror on disk with valid data (note that the last sector of the
     disk will be overwritten).  Add another disk to this mirror, so it will
     be synchronized with existing disk:

       gmirror label -v -b round-robin data da0
       gmirror insert data da1


Though in my case, da0 and da1 will be ad4 and ad5.  This seems to be
the one I'm looking for, I'm just scared of wiping out more than I
bargain for.

Andy

-- 
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**************
 
Hi Andy,
 
Although I assume you can't start from scratch, I think the article on this topic by the famous Dru Lavigne is very good:
 
http://www.onlamp.com/pub/a/bsd/2005/11/10/FreeBSD_Basics.html
 
This is what I've used to do it.
Now I did a google search and found:
 
http://www.onlamp.com/pub/a/bsd/2005/11/10/FreeBSD_Basics.html?page=2
 
And gmirror is in the handbook, if found it in:
 
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/geom-mirror.html
 
So these sources will give you a lot of knowledge.
 
I swear by gmirror, I had very good experience with it and will use it in the future again. I just need to find some time to attach the two identical HDD's to my via c7 system.
 
Brgds
Dino