Les Mikesell spake the following on 5/1/2006 9:32 PM: > On Tue, 2006-05-02 at 00:13, Mace Eliason wrote: >> I think the reason for the partitions not being on the same drive is >> because the old drive is the bootable drive and I changed the scsi ids >> of the drives to get it to work. I think it is using sba for the boot >> but centos is on sbb. > > It doesn't really boot from raid. It loads the kernel from > the underlying partition on the boot drive, then the kernel > detects the raid devices and decides how to activate them, > then it mounts them according to /etc/fstab. You should be > able to review the detection process with 'dmesg |less' > if you are interested. > >> I just need to make sure that the sync happens so that the info on sbb >> is what is synced. The info on sba is 1 month old this I have confirmed >> by mounting sba3 and looking at the dates of the last emails received on >> the server I couldn't mount sdb3 because it is the active partition. > > Be careful with your spelling... I assume you mean /dev/sda3 is the > old one. > >> So from what your saying below running mdadm as you have shown will it >> copy the good info on sdb to sda? > > Again, be careful. It will copy the currently active partition > to the one you are adding - so if you see the current version > now, that's what will be mirrored. In the case of /dev/sdb3 it > will go from sdb to sda. But /dev/sda1 is active now and will > be copied to /dev/sdb1. > >> I have to have this server ready for 7am or we will loose this >> contract. I can't believe I have spend all day on this. > > This is the sort of thing you should practice on a test > box so you are prepared to handle an actual problem in a > reasonable amount of time. > >> If I copy over the wrong info they will lose 1 months worth of emails. > > You can only copy from the active one to the one you > add. And by the way, having backups can be a good thing > too... > You might want to download the free Vmware server software and play with senarios like this. You can create installs with 2 drives in raid 1, and kill a drive and play with rebuilding. All virtual, so no damage to working systems. This is how I learned some of the nuances of linux software raid. -- MailScanner is like deodorant... You hope everybody uses it, and you notice quickly if they don't!!!!