I tested RAID 1 with differents size hard disk , it is work. You need first, execute command sfdisk -l /dev/hd_GOOD > partitions.txt Second execute command sfdisk /dev/hd_NEWDISK < partitons.txt. After recover process normal RAID recover. I hope to help you Adriano Frare Aleksandar Milivojevic wrote: > Joseph Cheng wrote: >> Hello all. I have a server with a linux software raid1 setup between >> two drives of the same model....one hard drive as primary ide master >> and second hard drive as secondary master. Now primary master hard >> drive is displaying a lot of SMART errors so I would like to remove it >> and replace with another drive....different brand but same size. >> Partitions are /dev/md0 till /dev/md5. I think I know what to do based >> on mdadm man page and this list's archives but there is no harm in >> confirming right? ;) From this post >> http://lists.centos.org/pipermail/centos/2006-April/063076.html I plan >> on removing the old partitions from the array like this..... mdadm >> /dev/mdx -r /dev/hdax. Then I will shut down the server, replace the >> hard drive, make the server boot from second IDE drive and hopefully >> boot into Centos. From there do I have to manually create each >> /dev/mdx partition and then re-add them like this....mdadm /dev/mdx -a >> /dev/hdax ? That is what I am not sure about whether I have to >> partiton the drive exactly like the old one or if Centos mdadm can do >> some magic for me with a blank drive. TIA!! > > Couple of things to watch out. > > What boot loader are you using? If it is Grub, check if it was > installed on partition, not in MBR of first drive. If it was in MBR, > there is a good chance you don't have it mirrored on second drive. > You'll need working boot loader (most likely Grub) on second drive in > order to boot from it. > > Disk size... It is next to impossible to find "different brand but same > size". If the label says 80GB, it means "somewhere around 80GB". You > want to look at LBA count (it's printed almost on all hard drives, but > often hard to find in specifications). It's basically the number of > sectors that the drive has. You want the drive that has at least the > number of sectors as your existing drive(s). If you already got the new > drive and it is few sectors short, all is not lost. You'll just have a > bit of additional work. You'll need to shrink some partition. Swap > partition is usually good candidate since it doesn't contain any data. > You can also shrink a partition that holds file system, but if you make > mistake you might end up loosing some data. Another thing to keep in > mind when shrinking partitions is that Linux stores RAID metadata at the > end of the partition. If you are shrinking partition that holds Linux > RAID device, the best thing (if it was RAID 1 volume) is to ditch the md > device for it, shrink the file system to smaller size, and recreate md > device. Your data should survive the operation. When shrinking file > system, have in mind you'll need to have some extra space of RAID > metadata information at the end of partition (you'll need to shrink file > system to be smaller than the final partition size). > > You'll need to partition the new drive manually. Remember to tag > partitions as "Linux raid autodetect" (by default fdisk will tag them as > "Linux"). Tag for Linux raid autodetect is fd. New partitions must be > the same size (in blocks) as the partitions you are replacing or larger. > If you make them larger, the extra space will be unused. > > If your boot loader was installed in the partition, it'll get mirrored > automatically. If it was in MBR, you'll have to install it by hand onto > the drive you just replaced. > > The rest should more or less go smooth. > > > ------------------------------------------------------------------------ > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos