On Fri, Nov 18, 2016 at 7:44 PM, Florian Gleixner
I recommend using mdraid and LVM2.
You can add disks to mdraids and you can change raid levels. See
https://serverhorror.wordpress.com/2011/01/27/migrating-raid-levels-in-linux...
Using md devices as physical devices for a lvm volume adds even more flexibility. If you swap old disks for new ones, you can add the new devices (as new md device) to expand the volume group, use pvmove to move data online to the new devices and then drop old devices from the volume group. Or better: you add new md devices and extend your logical volume.
If you use large disks, use mirrored devices whenever possible. Raid5 is not an option (as Lew already noted) and raid 6 is really slow! Growing a raid6 with another 10TB drive may take days!
So best is to add always 2 devices, create a mirror and add it to the logical volume.
See manpages of mdadm, pvcreate, pvmove, vgextendd, vgreduce, lvextend
Thanks Florian, I was hoping MDraid / LVM2 was a flexible enough option. To address my desire to use the largest drives I can going forward to keep the spindle count down, I assume I could buy them in pairs. 2x10TB now, maybe 2x12TB in 6 months, etc. Then use LVM to aggregate the RAID1 pairs. Thanks Greg -- Greg Freemyer -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org