From c325040e59438ceb369d39e511938154fe1e30ec Mon Sep 17 00:00:00 2001 From: Richard Laager Date: Sun, 17 Mar 2019 20:08:22 -0500 Subject: [PATCH] Debian/Ubuntu: Make /var/cache & /var/tmp optional --- Debian-Stretch-Root-on-ZFS.md | 22 +++++++++++----------- Ubuntu-18.04-Root-on-ZFS.md | 22 +++++++++++----------- 2 files changed, 22 insertions(+), 22 deletions(-) diff --git a/Debian-Stretch-Root-on-ZFS.md b/Debian-Stretch-Root-on-ZFS.md index d343f69..5576b7d 100644 --- a/Debian-Stretch-Root-on-ZFS.md +++ b/Debian-Stretch-Root-on-ZFS.md @@ -116,11 +116,14 @@ The primary goal of this dataset layout is to separate the OS from user data. Th # zfs create rpool/home # zfs create -o mountpoint=/root rpool/home/root # zfs create -o canmount=off rpool/var - # zfs create -o com.sun:auto-snapshot=false rpool/var/cache # zfs create -o canmount=off rpool/var/lib # zfs create rpool/var/log # zfs create rpool/var/spool + + If you wish to exclude these from snapshots: + # zfs create -o com.sun:auto-snapshot=false rpool/var/cache # zfs create -o com.sun:auto-snapshot=false rpool/var/tmp + # chmod 1777 /mnt/var/tmp If you use /opt on this system: # zfs create rpool/opt @@ -161,7 +164,6 @@ If you do nothing extra, `/tmp` will be stored as part of the root filesystem. A 3.4 Install the minimal system: - # chmod 1777 /mnt/var/tmp # debootstrap stretch /mnt # zfs set devices=off rpool @@ -258,17 +260,15 @@ Install GRUB to the disk(s), not the partition(s). [Until ZFS gains a systemd mount generator](https://github.com/zfsonlinux/zfs/issues/4898), there are races between mounting filesystems and starting certain daemons. In practice, the issues (e.g. [#5754](https://github.com/zfsonlinux/zfs/issues/5754)) seem to be with certain filesystems in `/var`, specifically `/var/log` and `/var/tmp`. Setting these to use `legacy` mounting, and listing them in `/etc/fstab` makes systemd aware that these are separate mountpoints. In turn, `rsyslog.service` depends on `var-log.mount` by way of `local-fs.target` and services using the `PrivateTmp` feature of systemd automatically use `After=var-tmp.mount`. # zfs set mountpoint=legacy rpool/var/log - # zfs set mountpoint=legacy rpool/var/tmp - # cat >> /etc/fstab << EOF - rpool/var/log /var/log zfs nodev,relatime 0 0 - rpool/var/tmp /var/tmp zfs nodev,relatime 0 0 - EOF + # echo rpool/var/log /var/log zfs nodev,relatime 0 0 >> /etc/fstab - If you created a /tmp dataset, do the same for it: + If you created a /var/tmp dataset: + # zfs set mountpoint=legacy rpool/var/tmp + # echo rpool/var/tmp /var/tmp zfs nodev,relatime 0 0 >> /etc/fstab + + If you created a /tmp dataset: # zfs set mountpoint=legacy rpool/tmp - # cat >> /etc/fstab << EOF - rpool/tmp /tmp zfs nodev,relatime 0 0 - EOF + # echo rpool/tmp /tmp zfs nodev,relatime 0 0 >> /etc/fstab 4.9 Optional (but recommended): Mount a tmpfs to /tmp diff --git a/Ubuntu-18.04-Root-on-ZFS.md b/Ubuntu-18.04-Root-on-ZFS.md index 885a53f..a743d04 100644 --- a/Ubuntu-18.04-Root-on-ZFS.md +++ b/Ubuntu-18.04-Root-on-ZFS.md @@ -140,11 +140,14 @@ With ZFS, it is not normally necessary to use a mount command (either `mount` or # zfs create rpool/home # zfs create -o mountpoint=/root rpool/home/root # zfs create -o canmount=off rpool/var - # zfs create -o com.sun:auto-snapshot=false rpool/var/cache # zfs create -o canmount=off rpool/var/lib # zfs create rpool/var/log # zfs create rpool/var/spool + + If you wish to exclude these from snapshots: + # zfs create -o com.sun:auto-snapshot=false rpool/var/cache # zfs create -o com.sun:auto-snapshot=false rpool/var/tmp + # chmod 1777 /mnt/var/tmp If you use /opt on this system: # zfs create rpool/opt @@ -193,7 +196,6 @@ If you do nothing extra, `/tmp` will be stored as part of the root filesystem. A 3.5 Install the minimal system: - # chmod 1777 /mnt/var/tmp # debootstrap bionic /mnt # zfs set devices=off rpool @@ -316,17 +318,15 @@ Install GRUB to the disk(s), not the partition(s). [Until ZFS gains a systemd mount generator](https://github.com/zfsonlinux/zfs/issues/4898), there are races between mounting filesystems and starting certain daemons. In practice, the issues (e.g. [#5754](https://github.com/zfsonlinux/zfs/issues/5754)) seem to be with certain filesystems in `/var`, specifically `/var/log` and `/var/tmp`. Setting these to use `legacy` mounting, and listing them in `/etc/fstab` makes systemd aware that these are separate mountpoints. In turn, `rsyslog.service` depends on `var-log.mount` by way of `local-fs.target` and services using the `PrivateTmp` feature of systemd automatically use `After=var-tmp.mount`. # zfs set mountpoint=legacy rpool/var/log - # zfs set mountpoint=legacy rpool/var/tmp - # cat >> /etc/fstab << EOF - rpool/var/log /var/log zfs nodev,relatime 0 0 - rpool/var/tmp /var/tmp zfs nodev,relatime 0 0 - EOF + # echo rpool/var/log /var/log zfs nodev,relatime 0 0 >> /etc/fstab - If you created a /tmp dataset, do the same for it: + If you created a /var/tmp dataset: + # zfs set mountpoint=legacy rpool/var/tmp + # echo rpool/var/tmp /var/tmp zfs nodev,relatime 0 0 >> /etc/fstab + + If you created a /tmp dataset: # zfs set mountpoint=legacy rpool/tmp - # cat >> /etc/fstab << EOF - rpool/tmp /tmp zfs nodev,relatime 0 0 - EOF + # echo rpool/tmp /tmp zfs nodev,relatime 0 0 >> /etc/fstab 4.12 Optional (but recommended): Mount a tmpfs to /tmp