Ubuntu/Debian: Use a variable for the disk

This simplifies a bunch of typing.  This does more strongly encourage
people to use /dev/disk/by-id naming, as e.g. ${DISK}-part1 does not
work if $DISK is /dev/sda.  This could be a considered a feature or a
bug, depending on one's perspective.

Debian-Buster-Root-on-ZFS.md

@@ -67,49 +67,54 @@ If you have a second system, using SSH to access the target system can be conven
 
 ## Step 2: Disk Formatting
 
-2.1  If you are re-using a disk, clear it as necessary:
+2.1  Set a variable with the disk name:
 
-If the disk was previously used in an MD array, zero the superblock:
+    DISK=/dev/disk/by-id/scsi-SATA_disk1
-
-    apt install --yes mdadm
-    mdadm --zero-superblock --force /dev/disk/by-id/scsi-SATA_disk1
-
-Clear the partition table:
-
-    sgdisk --zap-all /dev/disk/by-id/scsi-SATA_disk1
-
-2.2  Partition your disk(s):
-
-Run this if you need legacy (BIOS) booting:
-
-    sgdisk -a1 -n1:24K:+1000K -t1:EF02 /dev/disk/by-id/scsi-SATA_disk1
-
-Run this for UEFI booting (for use now or in the future):
-
-    sgdisk     -n2:1M:+512M   -t2:EF00 /dev/disk/by-id/scsi-SATA_disk1
-
-Run this for the boot pool:
-
-    sgdisk     -n3:0:+1G      -t3:BF01 /dev/disk/by-id/scsi-SATA_disk1
-
-Choose one of the following options:
-
-2.2a  Unencrypted or ZFS native encryption:
-
-    sgdisk     -n4:0:0        -t4:BF01 /dev/disk/by-id/scsi-SATA_disk1
-
-2.2b  LUKS:
-
-    sgdisk     -n4:0:0        -t4:8300 /dev/disk/by-id/scsi-SATA_disk1
 
 Always use the long `/dev/disk/by-id/*` aliases with ZFS.  Using the `/dev/sd*` device nodes directly can cause sporadic import failures, especially on systems that have more than one storage pool.
 
 **Hints:**
 * `ls -la /dev/disk/by-id` will list the aliases.
 * Are you doing this in a virtual machine? If your virtual disk is missing from `/dev/disk/by-id`, use `/dev/vda` if you are using KVM with virtio; otherwise, read the [troubleshooting](#troubleshooting) section.
-* If you are creating a mirror or raidz topology, repeat the partitioning commands for all the disks which will be part of the pool.
 
-2.3  Create the boot pool:
+2.2  If you are re-using a disk, clear it as necessary:
+
+If the disk was previously used in an MD array, zero the superblock:
+
+    apt install --yes mdadm
+    mdadm --zero-superblock --force $DISK
+
+Clear the partition table:
+
+    sgdisk --zap-all $DISK
+
+2.3  Partition your disk(s):
+
+Run this if you need legacy (BIOS) booting:
+
+    sgdisk -a1 -n1:24K:+1000K -t1:EF02 $DISK
+
+Run this for UEFI booting (for use now or in the future):
+
+    sgdisk     -n2:1M:+512M   -t2:EF00 $DISK
+
+Run this for the boot pool:
+
+    sgdisk     -n3:0:+1G      -t3:BF01 $DISK
+
+Choose one of the following options:
+
+2.3a  Unencrypted or ZFS native encryption:
+
+    sgdisk     -n4:0:0        -t4:BF01 $DISK
+
+2.3b  LUKS:
+
+    sgdisk     -n4:0:0        -t4:8300 $DISK
+
+If you are creating a mirror or raidz topology, repeat the partitioning commands for all the disks which will be part of the pool.
+
+2.4  Create the boot pool:
 
     zpool create -o ashift=12 -d \
         -o feature@async_destroy=enabled \
@@ -131,8 +136,7 @@ Always use the long `/dev/disk/by-id/*` aliases with ZFS.  Using the `/dev/sd*`
         -o feature@allocation_classes=enabled \
         -O acltype=posixacl -O canmount=off -O compression=lz4 -O devices=off \
         -O normalization=formD -O relatime=on -O xattr=sa \
-        -O mountpoint=/ -R /mnt \
+        -O mountpoint=/ -R /mnt bpool ${DISK}-part3
-        bpool /dev/disk/by-id/scsi-SATA_disk1-part3
 
 You should not need to customize any of the options for the boot pool.
 
@@ -142,38 +146,34 @@ GRUB does not support all of the zpool features. See `spa_feature_names` in [gru
 * If you are creating a mirror or raidz topology, create the pool using `zpool create ... bpool mirror /dev/disk/by-id/scsi-SATA_disk1-part3 /dev/disk/by-id/scsi-SATA_disk2-part3` (or replace `mirror` with `raidz`, `raidz2`, or `raidz3` and list the partitions from additional disks).
 * The pool name is arbitrary. If changed, the new name must be used consistently. The `bpool` convention originated in this HOWTO.
 
-2.4  Create the root pool:
+2.5  Create the root pool:
 
 Choose one of the following options:
 
-2.4a  Unencrypted:
+2.5a  Unencrypted:
 
     zpool create -o ashift=12 \
         -O acltype=posixacl -O canmount=off -O compression=lz4 \
         -O dnodesize=auto -O normalization=formD -O relatime=on -O xattr=sa \
-        -O mountpoint=/ -R /mnt \
+        -O mountpoint=/ -R /mnt rpool ${DISK}-part4
-        rpool /dev/disk/by-id/scsi-SATA_disk1-part4
 
-2.4b  LUKS:
+2.5b  LUKS:
 
     apt install --yes cryptsetup
-    cryptsetup luksFormat -c aes-xts-plain64 -s 512 -h sha256 \
+    cryptsetup luksFormat -c aes-xts-plain64 -s 512 -h sha256 ${DISK}-part4
-        /dev/disk/by-id/scsi-SATA_disk1-part4
+    cryptsetup luksOpen ${DISK}-part4 luks1
-    cryptsetup luksOpen /dev/disk/by-id/scsi-SATA_disk1-part4 luks1
     zpool create -o ashift=12 \
         -O acltype=posixacl -O canmount=off -O compression=lz4 \
         -O dnodesize=auto -O normalization=formD -O relatime=on -O xattr=sa \
-        -O mountpoint=/ -R /mnt \
+        -O mountpoint=/ -R /mnt rpool /dev/mapper/luks1
-        rpool /dev/mapper/luks1
 
-2.4c  ZFS native encryption:
+2.5c  ZFS native encryption:
 
     zpool create -o ashift=12 \
         -O acltype=posixacl -O canmount=off -O compression=lz4 \
         -O dnodesize=auto -O normalization=formD -O relatime=on -O xattr=sa \
         -O encryption=aes-256-gcm -O keylocation=prompt -O keyformat=passphrase \
-        -O mountpoint=/ -R /mnt \
+        -O mountpoint=/ -R /mnt rpool ${DISK}-part4
-        rpool /dev/disk/by-id/scsi-SATA_disk1-part4
 
 * The use of `ashift=12` is recommended here because many drives today have 4KiB (or larger) physical sectors, even though they present 512B logical sectors.  Also, a future replacement drive may have 4KiB physical sectors (in which case `ashift=12` is desirable) or 4KiB logical sectors (in which case `ashift=12` is required).
 * Setting `-O acltype=posixacl` enables POSIX ACLs globally. If you do not want this, remove that option, but later add `-o acltype=posixacl` (note: lowercase "o") to the `zfs create` for `/var/log`, as [journald requires ACLs](https://askubuntu.com/questions/970886/journalctl-says-failed-to-search-journal-acl-operation-not-supported)
@@ -331,7 +331,7 @@ Customize this file if the system is not a DHCP client.
     mount --rbind /dev  /mnt/dev
     mount --rbind /proc /mnt/proc
     mount --rbind /sys  /mnt/sys
-    chroot /mnt /bin/bash --login
+    chroot /mnt /usr/bin/env DISK=$DISK bash --login
 
 **Note:** This is using `--rbind`, not `--bind`.
 
@@ -356,8 +356,7 @@ Even if you prefer a non-English system language, always ensure that `en_US.UTF-
 
     apt install --yes cryptsetup
 
-    echo luks1 UUID=$(blkid -s UUID -o value \
+    echo luks1 UUID=$(blkid -s UUID -o value ${DISK}-part4) none \
-        /dev/disk/by-id/scsi-SATA_disk1-part4) none \
         luks,discard,initramfs > /etc/crypttab
 
 * The use of `initramfs` is a work-around for [cryptsetup does not support ZFS](https://bugs.launchpad.net/ubuntu/+source/cryptsetup/+bug/1612906).
@@ -377,10 +376,9 @@ Install GRUB to the disk(s), not the partition(s).
 4.8b  Install GRUB for UEFI booting
 
     apt install dosfstools
-    mkdosfs -F 32 -s 1 -n EFI /dev/disk/by-id/scsi-SATA_disk1-part2
+    mkdosfs -F 32 -s 1 -n EFI ${DISK}-part2
     mkdir /boot/efi
-    echo PARTUUID=$(blkid -s PARTUUID -o value \
+    echo PARTUUID=$(blkid -s PARTUUID -o value ${DISK}-part2) \
-        /dev/disk/by-id/scsi-SATA_disk1-part2) \
         /boot/efi vfat nofail,x-systemd.device-timeout=1 0 1 >> /etc/fstab
     mount /boot/efi
     apt install --yes grub-efi-amd64 shim-signed
@@ -465,7 +463,7 @@ Later, once the system has rebooted twice and you are sure everything is working
 
 5.6a  For legacy (BIOS) booting, install GRUB to the MBR:
 
-    grub-install /dev/disk/by-id/scsi-SATA_disk1
+    grub-install $DISK
 
 Note that you are installing GRUB to the whole disk, not a partition.
 

Ubuntu-18.04-Root-on-ZFS.md

@@ -59,49 +59,54 @@ If you have a second system, using SSH to access the target system can be conven
 
 ## Step 2: Disk Formatting
 
-2.1  If you are re-using a disk, clear it as necessary:
+2.1  Set a variable with the disk name:
 
-If the disk was previously used in an MD array, zero the superblock:
+    DISK=/dev/disk/by-id/scsi-SATA_disk1
-
-    apt install --yes mdadm
-    mdadm --zero-superblock --force /dev/disk/by-id/scsi-SATA_disk1
-
-Clear the partition table:
-
-    sgdisk --zap-all /dev/disk/by-id/scsi-SATA_disk1
-
-2.2  Partition your disk(s):
-
-Run this if you need legacy (BIOS) booting:
-
-    sgdisk -a1 -n1:24K:+1000K -t1:EF02 /dev/disk/by-id/scsi-SATA_disk1
-
-Run this for UEFI booting (for use now or in the future):
-
-    sgdisk     -n2:1M:+512M   -t2:EF00 /dev/disk/by-id/scsi-SATA_disk1
-
-Run this for the boot pool:
-
-    sgdisk     -n3:0:+1G      -t3:BF01 /dev/disk/by-id/scsi-SATA_disk1
-
-Choose one of the following options:
-
-2.2a  Unencrypted:
-
-    sgdisk     -n4:0:0        -t4:BF01 /dev/disk/by-id/scsi-SATA_disk1
-
-2.2b  LUKS:
-
-    sgdisk     -n4:0:0        -t4:8300 /dev/disk/by-id/scsi-SATA_disk1
 
 Always use the long `/dev/disk/by-id/*` aliases with ZFS.  Using the `/dev/sd*` device nodes directly can cause sporadic import failures, especially on systems that have more than one storage pool.
 
 **Hints:**
 * `ls -la /dev/disk/by-id` will list the aliases.
 * Are you doing this in a virtual machine? If your virtual disk is missing from `/dev/disk/by-id`, use `/dev/vda` if you are using KVM with virtio; otherwise, read the [troubleshooting](#troubleshooting) section.
-* If you are creating a mirror or raidz topology, repeat the partitioning commands for all the disks which will be part of the pool.
 
-2.3  Create the boot pool:
+2.2  If you are re-using a disk, clear it as necessary:
+
+If the disk was previously used in an MD array, zero the superblock:
+
+    apt install --yes mdadm
+    mdadm --zero-superblock --force $DISK
+
+Clear the partition table:
+
+    sgdisk --zap-all $DISK
+
+2.3  Partition your disk(s):
+
+Run this if you need legacy (BIOS) booting:
+
+    sgdisk -a1 -n1:24K:+1000K -t1:EF02 $DISK
+
+Run this for UEFI booting (for use now or in the future):
+
+    sgdisk     -n2:1M:+512M   -t2:EF00 $DISK
+
+Run this for the boot pool:
+
+    sgdisk     -n3:0:+1G      -t3:BF01 $DISK
+
+Choose one of the following options:
+
+2.3a  Unencrypted:
+
+    sgdisk     -n4:0:0        -t4:BF01 $DISK
+
+2.3b  LUKS:
+
+    sgdisk     -n4:0:0        -t4:8300 $DISK
+
+If you are creating a mirror or raidz topology, repeat the partitioning commands for all the disks which will be part of the pool.
+
+2.4  Create the boot pool:
 
     zpool create -o ashift=12 -d \
         -o feature@async_destroy=enabled \
@@ -118,8 +123,7 @@ Always use the long `/dev/disk/by-id/*` aliases with ZFS.  Using the `/dev/sd*`
         -o feature@userobj_accounting=enabled \
         -O acltype=posixacl -O canmount=off -O compression=lz4 -O devices=off \
         -O normalization=formD -O relatime=on -O xattr=sa \
-        -O mountpoint=/ -R /mnt \
+        -O mountpoint=/ -R /mnt bpool ${DISK}-part3
-        bpool /dev/disk/by-id/scsi-SATA_disk1-part3
 
 You should not need to customize any of the options for the boot pool.
 
@@ -129,28 +133,25 @@ GRUB does not support all of the zpool features. See `spa_feature_names` in [gru
 * If you are creating a mirror or raidz topology, create the pool using `zpool create ... bpool mirror /dev/disk/by-id/scsi-SATA_disk1-part3 /dev/disk/by-id/scsi-SATA_disk2-part3` (or replace `mirror` with `raidz`, `raidz2`, or `raidz3` and list the partitions from additional disks).
 * The pool name is arbitrary. If changed, the new name must be used consistently. The `bpool` convention originated in this HOWTO.
 
-2.4  Create the root pool:
+2.5  Create the root pool:
 
 Choose one of the following options:
 
-2.4a  Unencrypted:
+2.5a  Unencrypted:
 
     zpool create -o ashift=12 \
         -O acltype=posixacl -O canmount=off -O compression=lz4 \
         -O dnodesize=auto -O normalization=formD -O relatime=on -O xattr=sa \
-        -O mountpoint=/ -R /mnt \
+        -O mountpoint=/ -R /mnt rpool ${DISK}-part4
-        rpool /dev/disk/by-id/scsi-SATA_disk1-part4
 
-2.4b  LUKS:
+2.5b  LUKS:
 
-    cryptsetup luksFormat -c aes-xts-plain64 -s 512 -h sha256 \
+    cryptsetup luksFormat -c aes-xts-plain64 -s 512 -h sha256 ${DISK}-part4
-        /dev/disk/by-id/scsi-SATA_disk1-part4
+    cryptsetup luksOpen ${DISK}-part4 luks1
-    cryptsetup luksOpen /dev/disk/by-id/scsi-SATA_disk1-part4 luks1
     zpool create -o ashift=12 \
         -O acltype=posixacl -O canmount=off -O compression=lz4 \
         -O dnodesize=auto -O normalization=formD -O relatime=on -O xattr=sa \
-        -O mountpoint=/ -R /mnt \
+        -O mountpoint=/ -R /mnt rpool /dev/mapper/luks1
-        rpool /dev/mapper/luks1
 
 * The use of `ashift=12` is recommended here because many drives today have 4KiB (or larger) physical sectors, even though they present 512B logical sectors.  Also, a future replacement drive may have 4KiB physical sectors (in which case `ashift=12` is desirable) or 4KiB logical sectors (in which case `ashift=12` is required).
 * Setting `-O acltype=posixacl` enables POSIX ACLs globally. If you do not want this, remove that option, but later add `-o acltype=posixacl` (note: lowercase "o") to the `zfs create` for `/var/log`, as [journald requires ACLs](https://askubuntu.com/questions/970886/journalctl-says-failed-to-search-journal-acl-operation-not-supported)
@@ -307,7 +308,7 @@ Customize this file if the system is not a DHCP client.
     mount --rbind /dev  /mnt/dev
     mount --rbind /proc /mnt/proc
     mount --rbind /sys  /mnt/sys
-    chroot /mnt /bin/bash --login
+    chroot /mnt /usr/bin/env DISK=$DISK bash --login
 
 **Note:** This is using `--rbind`, not `--bind`.
 
@@ -337,8 +338,7 @@ If you prefer nano over vi, install it:
 
     apt install --yes cryptsetup
 
-    echo luks1 UUID=$(blkid -s UUID -o value \
+    echo luks1 UUID=$(blkid -s UUID -o value ${DISK}-part4) none \
-        /dev/disk/by-id/scsi-SATA_disk1-part4) none \
         luks,discard,initramfs > /etc/crypttab
 
 * The use of `initramfs` is a work-around for [cryptsetup does not support ZFS](https://bugs.launchpad.net/ubuntu/+source/cryptsetup/+bug/1612906).
@@ -358,10 +358,9 @@ Install GRUB to the disk(s), not the partition(s).
 4.8b  Install GRUB for UEFI booting
 
     apt install dosfstools
-    mkdosfs -F 32 -s 1 -n EFI /dev/disk/by-id/scsi-SATA_disk1-part2
+    mkdosfs -F 32 -s 1 -n EFI ${DISK}-part2
     mkdir /boot/efi
-    echo PARTUUID=$(blkid -s PARTUUID -o value \
+    echo PARTUUID=$(blkid -s PARTUUID -o value ${DISK}-part2) \
-        /dev/disk/by-id/scsi-SATA_disk1-part2) \
         /boot/efi vfat nofail,x-systemd.device-timeout=1 0 1 >> /etc/fstab
     mount /boot/efi
     apt install --yes grub-efi-amd64-signed shim-signed
@@ -446,7 +445,7 @@ Later, once the system has rebooted twice and you are sure everything is working
 
 5.6a  For legacy (BIOS) booting, install GRUB to the MBR:
 
-    grub-install /dev/disk/by-id/scsi-SATA_disk1
+    grub-install $DISK
 
 Note that you are installing GRUB to the whole disk, not a partition.