So this is where the real problems started up which led to my resolving the issues, but with one underlying question which I will get to shortly.
The goal is to setup two preconfigured RAID boxes which both come from different servers and connect them through one Adaptec U320 controller card on a dual Athlon MP Tyan motherboard. The two RAID boxes each contain 14 U320 SCSI drives setup in a JBOD configuration with one box being raid0 and the other raid5. Only one of the two boxes has exisitng data on it and blowing it away was out of the question. The problem I ran into was thought to be related strictly to the udev, hotplug, and creation of the extra /dev/md1 needed for the second box. After a couple of week of multiple emails with people and chasing this in circles I decided to blow away the new RAID box setup of RAID5 and rebuild it while the primary RAID box is still attached. First problem I encountered was in rebuilding the RAID array with 'mdadm --create ......' which didn't work. In short, I had to blow away the drive partitions, reboot, recreate the drive partitions then run the 'mdadm --create ...' to make it rebuild the array. Then when I ran disk druid to look at the drives I discovered what ended up being the root of all my problems. Before me was the listing for two RAID boxes and oh by the way both were labeled as /dev/md0. Now this is the whole source of the problems which I had already come upon through different means, but disk druid just proved my theory out.
So I rebuilt the array with the 'mdadm --create ...' command with the addiiton of specifying the /dev/md1 connection. This also required the manual creation of the /dev/md1 device file so the creation of the RAID device could take place. After creation and a reboot the udev actually discovered the second RAID with the superblock label for /dev/md1 and did it's thing to make everything work now. This is great!!
Now the question: Is there anything in mdadm allowing one to take a previously setup RAID box from another server and attach it to a second SCSI port and modify only the superblocks to change out the /dev/md0 to /dev/md1 or md2 or ....... so on?
This is very critical for managing the RAID boxes since if you already have one /dev/md0 connection you can not easily have a second device attached then connected to without errors or failure to setup the RAID box if it too is /dev/md0.
My solution to this at this point in time is to make these two RAID boxes be md4 and md5 while some of the other boxes become md0, md1, md2, md3, and so on. Of course I will need to blow away all the data and then rebuild the arrays from tapes.
Thanks for your time,
Bill Cronk - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
