{{tag>[zfs libvirt]}}

====== ZFS ======

<code bash>
apt install zfsutils-linux
</code>

<code>
sudo zfs list
</code>

create filesystem '''lab''' on '''LXD''' pool
<code>
sudo zfs create LXD/lab
sudo zfs set mountpoint=/lab LXD/lab
</code>

<code>
sudo zfs destroy LXD/lab
</code>

===== create pool =====

Pool can be created on disk or partition. In case of partition this is an example
<code>
Number  Start (sector)    End (sector)  Size       Code  Name
   1         1026048        74426367   35.0 GiB    8300  Linux filesystem
   2            2048         1026047   500.0 MiB   EF02  
   3        74426368        76474367   1000.0 MiB  8200  
   4        76474368       976756735   429.3 GiB   BF01  # <------- zfs
   5       976756736       976773119   8.0 MiB     BF07  # ???
</code>

<code>
zpool create lxd /dev/sda4
</code>

===== docker =====

<code>
systemctl stop docker
rm -fR /var/lib/docker
zfs create -o mountpoint=/var/lib/docker rpool/docker-root
zfs create -o mountpoint=/var/lib/docker/volumes rpool/docker-volumes
systemctl start docker
</code>

/etc/docker/daemon.json
<code>
{
  "default-address-pools":
  [
    {"base":"172.16.0.0/21","size":26}
  ],
  "storage-driver": "zfs",
  "features": {
    "buildkit" : true
  }
}

</code>


===== libvirt =====


add ZFS pool to libvirt
<code>
# in bionic
apt install libvirt-daemon-driver-storage-zfs && systemctl restart libvirtd

# create zfs filesystem
zfs create rpool/libvirt

virsh pool-define-as --name zfspool --source-name rpool/libvirt --type zfs
virsh pool-start zfspool
virsh pool-autostart zfspool
</code>

create volume (not possibile in virt-manager)
<code>
virsh vol-create-as --pool zfspool --name maas2 --capacity 10G
</code>

destroy volume
<code>
virsh vol-delete --pool zfspool maas2
</code>

add volume to instance

create file mydevice.xml
<code>
<disk type='block' device='disk'>
      <driver name='qemu' type='raw' cache='none'/>
      <source dev='/dev/zvol/rpool/libvirt/juju-controller'/>
      <target dev='vda' bus='virtio'/>
</disk>
</code>

add volume
<code>
virsh attach-device --config juju-controller mydevice.xml
</code>

===== virtualbox =====

create volume
<code bash>
zfs create -V 50G rpool/win7
</code>

create vmdk file that point /dev/zvol/rpool/win7 (/opt/vms/win7.vmdk keeps little)
<code>
VBoxManage internalcommands createrawvmdk -filename /opt/vms/win7.vmdk -rawdisk /dev/zvol/rpool/win7
</code>

now use /opt/vms/win7.vmdk file as virtual hard disk for virtualbox guest
===== tuning =====

pool on SSD https://storagetuning.wordpress.com/2011/12/01/zfs-tuning-for-ssds/
<file yaml /etc/systctl.conf>
vfs.zfs.l2arc_noprefetch=0
</file>

===== zfs root from live system  =====

<code bash>
zpool export rpool
zpool import -R /mnt rpool

umount everything inside /mnt

zfs mount rpool/ROOT/ubuntu


zfs set devices=off rpool
mount --rbind /dev  /mnt/dev
mount --rbind /proc /mnt/proc
mount --rbind /sys  /mnt/sys
chroot /mnt /bin/bash --login

... work here

exit
mount | grep -v zfs | tac | awk '/\/mnt/ {print $3}' | xargs -i{} umount -lf {}
zpool export rpool
reboot

</code>

===== remote replication =====

in origin make a snapshot of volume 
<code bash>
zfs snap storage/cimiteriali@snap1
</code>

destination volume cannot be exists
<code bash>
zfs send -R storage/cimiteriali@snap1 | pv | ssh zfs1 zfs recv -F -u rpool/cimiteriali
# zfs destroy storage/cimiteriali@snap1
</code>

on destination destroy snapshot to have volume
<code bash>
zfs destroy rpool/cimiteriali@snap1

# volsize ?
zfs get volsize,reservation rpool/cimiteriali
zfs set volsize=20G rpool/cimiteriali
zfs get volsize,reservation rpool/cimiteriali
</code>

==== syncoid ====

  * https://github.com/jimsalterjrs/sanoid

<code>
apt install pv lzop mbuffer
wget https://raw.githubusercontent.com/jimsalterjrs/sanoid/master/syncoid -O /usr/local/bin/syncoid
chmod +x /usr/local/bin/syncoid
</code>

using from server zfs1 (to server zfs2)
<code>
syncoid rpool/share-os root@zfs2:rpool/share-os
</code>
===== incremental backup =====

consider a FS rpool/test

<code bash>
FS=rpool/test

# make a first snapshot
zfs snapshot rpool/test@snap01
</code>

if files are added to FS used space of FS grow 
<code bash>
sync && zfs list -t all -r $FS
GROW --->rpool/test      200M   138G   200M  /test
         rpool/test@01    64K      -   100M  -
</code>

if files are changed in FS used space of SNAP grow
<code bash>
sync && zfs list -t all -r $FS
         rpool/test      200M   138G   200M  /test
GROW --->rpool/test@01   100M      -   100M  -
</code>


------> CRYPTOLOCKER grows SNAP

check crypto locker every day
<code bash>
LIMIT_MB=100
FS=rpool/test

USED=$(zfs get -Hp used $FS@01 | cut -f3)
if [ $USED -gt $(($LIMIT_MB*1000*1000)) ]; then
   echo "CRYPTOLOCKER detected"
   
fi
</code>

===== swap =====

<code>
zfs create -V 4G -b $(getconf PAGESIZE) -o compression=zle \
      -o logbias=throughput -o sync=always \
      -o primarycache=metadata -o secondarycache=none \
      -o com.sun:auto-snapshot=false rpool/swap

mkswap -f /dev/zvol/rpool/swap
</code>

<code>
echo /dev/zvol/rpool/swap none swap defaults 0 0 >> /etc/fstab
swapon -av
</code>