Hi gang, I currently have /boot and / (root) on raid 1 with mdadm. Which is useful for me specially when I patch the server because I break the mirror prior the patching and if something goes wrong is pretty straight forward to synchronize the mirror the other way around and fall back all the changes. I recently discovered that LVM allows us to create a raid 1 without mdadm, as I show below. You should use 3 hard disks to do a mirror, a third one for the lvm log file, makes sense.
At this point I have two main concerns: 1. Which would be the procedure to fall back the changes? How can I mirror the disks the other way around and roll back any change? 2. Is it possible to encapsulate /boot file system into LVM and if it is possible, how do you configure GRUB2? Please let me know your thoughts. Thanks Andrés- ························································ /* LVM mirror procedure */ I have 3 disks /dev/sd[abd]. Sda is partitioned, sdb is same size than sda and sdd is a small third disk. Debian:~# sfdisk -l /dev/sda Disk /dev/sda: 522 cylinders, 255 heads, 63 sectors/track Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End #cyls #blocks Id System /dev/sda1 * 0+ 30 31- 248976 83 Linux /dev/sda2 31 521 491 3943957+ 8e Linux LVM [snip] 1. I create the pvs # pvcreate /dev/sd[bd] Check: # pvs PV VG Fmt Attr PSize PFree /dev/sda2 Debian lvm2 a- 3.76G 0 /dev/sdb Debian lvm2 a- 4.00G 4.00G /dev/sdc1 SwapVG lvm2 a- 192.00M 0 /dev/sdd Debian lvm2 a- 196.00M 196.00M 2. Add the new PVs into the root volume group # vgextend Debian /dev/sd[bd] Check: # pvs PV VG Fmt Attr PSize PFree /dev/sda2 Debian lvm2 a- 3.76G 0 /dev/sdb Debian lvm2 a- 4.00G 4.00G /dev/sdc1 SwapVG lvm2 a- 192.00M 0 /dev/sdd Debian lvm2 a- 196.00M 196.00M 3. Mirror the data (in this case I'll use sdb to mirror sda and sdd as a third disk) # lvconvert -m1 /dev/Debian/root /dev/sdb /dev/sdd /dev/cdrom: open failed: Read-only file system /dev/Debian/root: Converted: 5.3% /dev/Debian/root: Converted: 12.4% /dev/Debian/root: Converted: 20.4% /dev/Debian/root: Converted: 25.7% /dev/Debian/root: Converted: 29.5% /dev/Debian/root: Converted: 32.9% /dev/Debian/root: Converted: 36.6% /dev/Debian/root: Converted: 40.3% /dev/Debian/root: Converted: 43.9% /dev/Debian/root: Converted: 47.5% /dev/Debian/root: Converted: 51.2% /dev/Debian/root: Converted: 54.8% /dev/Debian/root: Converted: 58.3% /dev/Debian/root: Converted: 61.9% /dev/Debian/root: Converted: 65.5% /dev/Debian/root: Converted: 69.2% /dev/Debian/root: Converted: 72.8% /dev/Debian/root: Converted: 76.5% /dev/Debian/root: Converted: 80.0% /dev/Debian/root: Converted: 83.6% /dev/Debian/root: Converted: 87.4% /dev/Debian/root: Converted: 91.0% /dev/Debian/root: Converted: 94.6% /dev/Debian/root: Converted: 98.2% /dev/Debian/root: Converted: 100.0% Logical volume root converted. Check: Debian:~# lvs -a -o +devices LV VG Attr LSize Origin Snap% Move Log Copy% Convert Devices root Debian mwi-ao 3.54G root_mlog 100.00 root_mimage_0(0),root_mimage_1(0) [root_mimage_0] Debian iwi-ao 3.54G /dev/sda2(0) [root_mimage_1] Debian iwi-ao 3.54G /dev/sdb(0) [root_mlog] Debian lwi-ao 4.00M /dev/sdd(0) swap_1 Debian -wi-ao 228.00M /dev/sda2(905) SwapVol SwapVG -wi-ao 192.00M /dev/sdc1(0) You can break the mirror with # lvconvert -m0 Debian