6 ms·

I've been using zfs on Debian for over half a year now. I've been really happy with the stability, going through a handful of power outages and the addition of

by gen3 7y ago

I've been using zfs on Debian for over half a year now. I've been really happy with the stability, going through a handful of power outages and the addition of another drive.

dev_dull 7y ago
Me too. I’ve been really surprised at how easy it is. Even migrating to a fresh OS was a breeze and didn’t require me backing up any configs.
- steeleduncan 7y ago
  Do you mean ZFS as root or as a data partition? and when you say migrating to a fresh OS do you mean the Stretch to Buster upgrade? If so, it is great to hear it is working so well now.
  - GrayShade 7y ago
    Not the grandparent, but I've moved a running system from one ZFS pool to another without physically touching the computer. The OS was running off a ZFS root.
  - dev_dull 7y ago
    ZFS data volume. Haven't tried root yet (wasn't easily available when I created the volume). Still, a data volume in ZFS is so much better than the traditional md raid. Won't go back.
gralx 7y ago
ZFS lets me back up every `apt-get` action, which is useful on Debian Testing: /etc/apt/apt.conf.d/71backup DPkg::Pre-Install-Pkgs {"/sbin/zfs snapshot rpool/ROOT/debian@apt-get_$(date '+%Y-%m-%d-%H%M%S')";}; When I inevitably break Debian with no time to troubleshoot, I do # zfs list -t snapshot | grep apt\-get ... # zfs rollback -r rpool/ROOT/debian@apt-get_<insert time stamp here>
- dddddaviddddd 7y ago
  I've set up something similar on FreeBSD with just a shell function wrapping pkg and port, very handy.
- isostatic 7y ago
  Nice. I haven't touched ZFS since it first came out on Solaris around 2008ish (we had a 48 drive "x4500", great hardware, but solaris :/ ) Are the snapshots instant? I'd be tempted to replace "sudo" with something that snapshotted them too!
  - GrayShade 7y ago
    > Are the snapshots instant? Yes. But you have to remember to delete the old ones at some point.
  - masklinn 7y ago
    > Are the snapshots instant? Yes, it just copies & stores the block at the top of the filesystem[0], in the same way naming a git tree will keep its content recursively alive. However all the data in the snapshot is retained as-is until the snapshot is destroyed, so as the system keeps being used and diverges from the snapshot the snapshot is slowly going to "increase in size" compared to the live FS. [0] there's also a more recent "checkpoint" concept which "saves" the entire pool by copying the uberblock.
  - zenexer 7y ago
    The actual act of snapshotting doesn’t do a whole lot. I believe ZFS uses CoW for that purpose. If you modify a file after a snapshot, the file (or block) will be copied first. Normally, with CoW, the original would then be marked as free space available for writing, but if a snapshot exists, it will be preserved. (This is a general concept; I don’t know the nuances of ZFS’ approach.)
    - isostatic 7y ago
      I thought that was the case, but in more recent times they only snapshotting I've done is on AWS instances which take forever

by gen3 7y ago

I've been using zfs on Debian for over half a year now. I've been really happy with the stability, going through a handful of power outages and the addition of another drive.

dev_dull 7y ago

Me too. I’ve been really surprised at how easy it is. Even migrating to a fresh OS was a breeze and didn’t require me backing up any configs.

steeleduncan 7y ago
Do you mean ZFS as root or as a data partition? and when you say migrating to a fresh OS do you mean the Stretch to Buster upgrade? If so, it is great to hear it is working so well now.
- GrayShade 7y ago
  Not the grandparent, but I've moved a running system from one ZFS pool to another without physically touching the computer. The OS was running off a ZFS root.
- dev_dull 7y ago
  ZFS data volume. Haven't tried root yet (wasn't easily available when I created the volume). Still, a data volume in ZFS is so much better than the traditional md raid. Won't go back.

gralx 7y ago

ZFS lets me back up every `apt-get` action, which is useful on Debian Testing: /etc/apt/apt.conf.d/71backup DPkg::Pre-Install-Pkgs {"/sbin/zfs snapshot rpool/ROOT/debian@apt-get_$(date '+%Y-%m-%d-%H%M%S')";}; When I inevitably break Debian with no time to troubleshoot, I do # zfs list -t snapshot | grep apt\-get ... # zfs rollback -r rpool/ROOT/debian@apt-get_<insert time stamp here>

dddddaviddddd 7y ago
I've set up something similar on FreeBSD with just a shell function wrapping pkg and port, very handy.
isostatic 7y ago
Nice. I haven't touched ZFS since it first came out on Solaris around 2008ish (we had a 48 drive "x4500", great hardware, but solaris :/ ) Are the snapshots instant? I'd be tempted to replace "sudo" with something that snapshotted them too!
- GrayShade 7y ago
  > Are the snapshots instant? Yes. But you have to remember to delete the old ones at some point.
- masklinn 7y ago
  > Are the snapshots instant? Yes, it just copies & stores the block at the top of the filesystem[0], in the same way naming a git tree will keep its content recursively alive. However all the data in the snapshot is retained as-is until the snapshot is destroyed, so as the system keeps being used and diverges from the snapshot the snapshot is slowly going to "increase in size" compared to the live FS. [0] there's also a more recent "checkpoint" concept which "saves" the entire pool by copying the uberblock.
- zenexer 7y ago
  The actual act of snapshotting doesn’t do a whole lot. I believe ZFS uses CoW for that purpose. If you modify a file after a snapshot, the file (or block) will be copied first. Normally, with CoW, the original would then be marked as free space available for writing, but if a snapshot exists, it will be preserved. (This is a general concept; I don’t know the nuances of ZFS’ approach.)
  - isostatic 7y ago
    I thought that was the case, but in more recent times they only snapshotting I've done is on AWS instances which take forever