Zfs
This is not a complete article: This is a draft, a work in progress that is intended to be published into an article, which may or may not be ready for inclusion in the main wiki. It should not necessarily be considered factual or authoritative.
ZFS is a combined file system and logical volume manager designed by Sun Microsystems. ZFS can scale to very large file system sizes and supports compression.
Installing ZFS
Starting with the image Ubuntu-18.04-Bionic-x64-2018-09
Ensure your package list is up-to-date and also do upgrades of your installed packages. While it isn't strictly nessacary to upgrade your installed packages it is a good idea.
[name@server]$ sudo apt-get update
[name@server]$ sudo apt-get dist-upgrade -y
Next install ZFS
[name@server]$ sudo apt-get install zfsutils-linux
Starting with the image CentOS-7-x64-2018-09
[name@server]$ sudo yum install http://download.zfsonlinux.org/epel/zfs-release.el7_5.noarch.rpm
...
Total size: 2.9 k
Installed size: 2.9 k
Is this ok [y/d/N]: y
...
hmm... this is looking strangely more complicated, see for example [1]
Starting with the image Fedora-Cloud-Base-29-1.2
to be written!
Using ZFS
Create a zpool and zfs file system
[name@server]$ sudo zpool create -f data /dev/vdb /dev/vdc
Turn on and choose a compression algorithim
[name@server]$ sudo zfs set compression=lz4 data
Check settings
[name@server]$ sudo zfs get all data
Create a dataset within the data zpool
[name@server]$ sudo zfs create -p data/www
Add a new volume
[name@server]$ sudo zpool add data /dev/vde
Check pool status
[name@server]$ sudo zpool status data
Destroy a zpool
[name@server]$ sudo zpool destroy data
Notes
While in theory it should be possible to use ZFS with resizing volumes in OpenStack in practices this has not been straight forward and is better to be avoided if possible.