----- Original Message ----- From: "Stuart Sears" <stu...@sjsears.com> To: "Hampshire LUG Discussion List" <hampshire@mailman.lug.org.uk> Sent: Saturday, March 28, 2009 4:08 PM Subject: Re: [Hampshire] Simple RAID problem
> Rob Malpass wrote: >> Hi all >> >> Trying to setup raid (on Ubuntu 8.1) with the command >> >> mdadm --assemble /dev/md0 /dev/sdb /dev/sdc >> >> and receiving the error no recognisable superblock on /dev/sdb >> >> The thing is I can mount both drives having formatted them to ext3 >> previously. > > mdadm --assemble is used to reconstruct an existing array, not create a > new one. > > For that you want mdadm --create (or -C for those of us who dislike > typing for typing's sake) > > what kind of RAID array are you trying to configure? > RAID 1 mirror? > > Are you sure you used the entire disk in each case and not individual > partitions? > >> I don't know what superblock means but I thought it meant that the >> drive's not formatted - which it obviously is if I can mount and >> read/write to it. > > nope, it means that the drive has never been part of a RAID array, which > it won't have been unless you already set it up :) > >> I must be doing something obvious wrong - but can't see what. To >> the best of my knowledge I've followed the guide at > > ** LONG-WINDED RAID INSTRUCTIONS ** [snip] Brilliant - thanks Hugo and Stuart for your advice. AFAIK I've now setup raid1 across two devices on a virtual machine. The thing is - how do I verify this? As I understand it - everything I now send to /dev/md0 (which I've mounted under /mnt) is sent to both /dev/sdb and /dev/sdc simultaneously. Presumably (I've not tried) but it won't just let me mount them somewhere else so I can see what's going on as they're now part of a raid device and won't contain ext3 filesystems - is that right? Thanks again - assuming I can verify it - I'm just the purchase of the hardware away from a DIY Drobo at a fraction of the cost * Cheers Rob * Yes yes - I know Drobo has some other nice features which I'm not setting up here. -- Please post to: Hampshire@mailman.lug.org.uk Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --------------------------------------------------------------
