I'm playing with using LVM to concatenate a number of old disks into one big disk. I'd like to use /etc/hdparm.conf to modify the spin-down times at boot, so that most of these disks spin down asap. My problem is that the device identifiers change frequently. LVM doesn't seem to struggle with this at all - it knows which HD at located at which /dev. I've considered using UUID or label and going through /dev/disk/by-*, but I'm not having any luck -- as shown below, the uuid's are not showing up, and I can't find a method to label a disk with an "LVM2_member" filesystem. I suppose I could install a normal FS on them and then use LVM on top of that in one partition - perhaps that's what the setup is supposed to look like
hamiltont@pooter:/dev$ sudo blkid
/dev/sda1: UUID="25e6c117-83bc-456b-beff-f8e8be1398d5" TYPE="ext2"
/dev/sda5: UUID="qP202o-8a6x-XoKu-jImN-jaCw-AKfS-u1X6RD" TYPE="LVM2_member"
/dev/mapper/pooter-root: UUID="eafb43ec-ad9a-40f0-a052-f00a803649ea" TYPE="ext4"
/dev/mapper/pooter-swap_1: UUID="18ca9cd8-e877-496e-ab31-96d2353306ae" TYPE="swap"
/dev/sdb: UUID="8Uy1IL-R1Jy-A2I0-U7cO-PtPl-A1SR-LIBLo3" TYPE="LVM2_member"
/dev/mapper/pooter-media: UUID="562e9317-5703-472c-b14a-7976f43ec62d" TYPE="ext4"
/dev/sdc: UUID="KGiRXv-eLV0-aY0m-Cg4N-PQ0y-WGCr-hYQ5MW" TYPE="LVM2_member"
hamiltont@pooter:/dev$ ls disk/by-uuid/
0B450E5E6B7A88DD 25e6c117-83bc-456b-beff-f8e8be1398d5 70D6-1701 d2becea8-1d8a-3de8-a810-3f399db66277
18ca9cd8-e877-496e-ab31-96d2353306ae 562e9317-5703-472c-b14a-7976f43ec62d BF9E-19DE eafb43ec-ad9a-40f0-a052-f00a803649ea
hamiltont@pooter:/dev$ sudo fdisk -l
Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000a7ec0
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 499711 248832 83 Linux
/dev/sda2 501758 312580095 156039169 5 Extended
/dev/sda5 501760 312580095 156039168 8e Linux LVM
Disk /dev/mapper/pooter-root: 157.9 GB, 157902962688 bytes
255 heads, 63 sectors/track, 19197 cylinders, total 308404224 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/pooter-root doesn't contain a valid partition table
Disk /dev/mapper/pooter-swap_1: 1879 MB, 1879048192 bytes
255 heads, 63 sectors/track, 228 cylinders, total 3670016 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/pooter-swap_1 doesn't contain a valid partition table
Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/sdb doesn't contain a valid partition table
Disk /dev/sdc: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/sdc doesn't contain a valid partition table
Disk /dev/mapper/pooter-media: 660.1 GB, 660141506560 bytes
255 heads, 63 sectors/track, 80257 cylinders, total 1289338880 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/pooter-media doesn't contain a valid partition table
