I would avoid any LVM implementations, while it allows you to resize partitions, if the LVM corrupts during resize, it corrupts on all mirrors and so removes your redundancy in a single blow. But then it's always good to remember that raid mirrors, mirror mistakes. How many discs is your physical server limited too anyway? Raid 5 can not be increased in size live, but it's implemention will allow for any number of discs over... 3 I believe, also alot of hardware implemention work well with hot spares to rebuild failed discs live, not sure if RAID 10 offers this same functionality. RAID 10 vs 5 issues often come down to vendor implementations. Also if you have a RAID 10 you can not add single discs, you have to add full raid 1s to your raid 0, this would require rebuilding as it goes anyway since the stripes would have to be distributed across the raid 0. You can still add a raid 1 next to a raid 5, or even add a raid 5 next to a raid 5.
Personally I think the idea of changing raid layouts live is not a good idea anyway, it's good to go with a solid raid layout that has one or two hotspares (depending on size of the array) incase of disc failure, to instantly restore any lost redundancy.
Last edited by r3sistance; 02-09-2009 at 07:00 AM.