Copying a partition live?
I want to go from a 0+1 raid made up of 10 9GB drives to a 0+1 raid made up of 10 18GB drives. I am using sds on solaris9 and my disks are in d1000s. My plan would be to break the mirror and remove one of the stripes made up of 9GB drives then put in the 18GB drives and remake the stripe. Then copy the data over and then remake the other half of the mirror with 18GB drives and sync that mirror up. My question is can this be done live? Can I take all the data from my 9GB drives to my 18GB drives while my users are still active on the machine and not lose any of there data? As far as I know sds will not let me sync 2 meta devices of different sizes and still retain the larger capacity. I was also looking at liveupgrade but am not sure how it would work on just upgrading a non-boot partition. In the past I齰e just taken the system down and copied data across but this time I齞 like to minimize my downtime since this upgrade will impact all my users. Any ideas?
[984 byte] By [
osu] at [2007-11-25 22:59:55]
# 1
You are right in that SDS will not let you have mirrors containing different sizes of disks. It will always default to the smaller size disk.
The only way I could think about doing this would be as follows:
1. Break the mirror.
2. Use one side of the mirror to create an archive / backup of the filesystem.
3. Replace the disks relating to the boken side of the mirror.
4. Use SDS and create one side of the 0+1 raid over the larger disks, making sure that you put it in as a new metadevice and not the old one, so in effect it would be a completely new 0+1 raid config.
5. Restore the data from the archive / backup to the new upgraded 0+1 raid.
6. At this stage you are going to have to sort out the OS mounts and point them to the new 0+1 raid and away from the old one. This will probably mean stopping applications, etc briefely and editing /etc/vfstab, etc files.
7. Replace the last set of the older disks
8. Add the last disks to SDS and to the new 0+1 raid config. They should then sync as normal.
9. Now you will have to sort of SDS and remove any unused metadevices that might be left.
The above is a bit messy but can be done live with the exception of a brief interruption to change the mounts for the 0+1 raid config. To be honest it might be worth considering scheduling downtime and backing up, replacing all disks then restoring the data once the 0+1 raid has been setup, that might be lenghty but it does work.
