How to configure Stratis Filesystem on CentOS 8

In this article, you will learn how to configure Stratis Filesystem on CentOS 8 or Redhat based Linux distros. #centlinux #linux #filesystem

What is Stratis Filesystem?

Stratis is a Linux local storage management tool that aims to enable easy use of advanced storage features such as thin provisioning, snapshots, and pool-based management & monitoring.

Stratis daemon is originally developed by Red Hat. Stratis is written in RUST language and distributed under Mozilla Public License 2.0. Stratis provides ZFS/Btrfs-style features by integrating layers of existing technology: Linux’s device mapper subsystem, and the XFS filesystem.

In this article, we will install and configure Stratis local storage on CentOS 8.

Stratis Storage Features

Stratis storage provides following advanced features.

• Thin Provisioning
• Pool Based Management and Monitoring
• FileSystem Snapshots

Stratis Storage Building Blocks

To understand Stratis Storage architecture, you need know the following three buidling blocks.

• Block Device: A block device can be a disk, partition or Logical Volume (LVM).
• Storage Pool: A Stratis storage pool consist of one or more Block devices.
• FileSystem: A FileSystem is a final ready to mount storage. It is provisioned from a Storage Pool.

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Environment Specification

We have provisioned virtual machine with minimally installed CentOS 8 with following specification.

• CPU – 3.4 Ghz (2 cores)
• Memory – 1 GB
• Storage – 20 GB
• Operating System – CentOS Linux 8.0
• Hostname – stratis-01.centlinux.com
• IP Address – 192.168.116.206 /24

Install Stratis Filesystem on CentOS 8

Connect with stratis-01.centlinux.com using ssh as root user.

To setup Stratis Filesystem on CentOS 8, we have to install following two packages.

• stratisd – Stratis Daemon
• stratis-cli – Command-line interface to manage stratis local storage.

Both packages are available in default dnf repository, therefore, we are installing it using dnf command.

# dnf install -y stratisd stratis-cli

Installer automatically enables the stratisd service. We are only required to start stratisd service once.

# systemctl start stratisd.service

Stratis has been successfully installed on CentOS 8.

Create Stratis Storage Pools

We have added four hard disks (10GB each) in our CentOS 8 virtual machine. We will use these disks as block devices for our Stratis storage pools.

# lsblk | grep 'sd[b-e]'
sdb    8:16   0   10G  0 disk
sdc    8:32   0   10G  0 disk
sdd    8:48   0   10G  0 disk
sde    8:64   0   10G  0 disk

Check current storage pools.

# stratis pool list
Name    Total Physical Size  Total Physical Used

Right now, we have no storage pool defined.

Let’s create a Stratis storage pool using /dev/sdb block device.

# stratis pool create db_pool /dev/sdb

Check current storage pools again.

# stratis pool list
Name       Total Physical Size  Total Physical Used
db_pool                 10 GiB               52 MiB

Add a Block Device to Existing Stratis Storage Pool

Let’s add our second disk to the db_pool stratis storage pool.

# stratis pool add-data db_pool /dev/sdc

Check current storage pools list.

# stratis pool list
Name       Total Physical Size  Total Physical Used
db_pool                 20 GiB               56 MiB

You can see that the total size of the db_pool has been increased.

Create Stratis Storage Pool from Multiple Block Devices

We can alternatively, create a pool using multiple block devices in a single command.

# stratis pool create backup_pool /dev/sdd /dev/sde

Check current storage pools now.

# stratis pool list
Name       Total Physical Size  Total Physical Used
backup_pool             20 GiB               56 MiB
db_pool                 20 GiB               56 MiB

Create Stratis FileSystems

We have a Stratis storage pool, we can now use it to provision Stratis filesystems as follows.

# stratis fs create db_pool prod_db_fs
# stratis fs create db_pool test_db_fs

Check the list of Stratis filesystems.

# stratis fs list
Pool Name  Name        Used     Created            Device                       UUID
db_pool    prod_db_fs  546 MiB  Dec 17 2019 22:22  /stratis/db_pool/prod_db_fs  d62f6884dffc40a6b8024784b7f60ca8
db_pool    test_db_fs  546 MiB  Dec 17 2019 22:22  /stratis/db_pool/test_db_fs  9ce32861f56b408597550d88e9bf5a44

Mounting Stratis FileSystems

We have create two Stratis filesystems, one for our Production database (prod_db_fs) and the other for the Test database (test_db_fs).

Now it’s time to mount these filesystems.

To mount these filesystems, we need to identify the UUID of the filesystems. We can obtain the UUID using following command.

# blkid | grep /dev/mapper/stratis
/dev/mapper/stratis-1-c943c04939f5432cbe4d3d9985cd462e-thin-fs-d62f6884dffc40a6b8024784b7f60ca8: UUID="d62f6884-dffc-40a6-b802-4784b7f60ca8" TYPE="xfs"
/dev/mapper/stratis-1-c943c04939f5432cbe4d3d9985cd462e-thin-fs-9ce32861f56b408597550d88e9bf5a44: UUID="9ce32861-f56b-4085-9755-0d88e9bf5a44" TYPE="xfs"

We can use these UUIDs to persistently mount our Stratis filesystems.

Create directories to mount Stratis filesystems.

# mkdir /mnt/{prod,test}

Edit /etc/fstab to add automount entries.

# vi /etc/fstab

Add entries for our Stratis filesystems therein.

UUID=d62f6884-dffc-40a6-b802-4784b7f60ca8       /mnt/prod       xfs     defaults,x-systemd.requires=stratisd.service    0 0
UUID=9ce32861-f56b-4085-9755-0d88e9bf5a44       /mnt/test       xfs        defaults,x-systemd.requires=stratisd.service    0 0

Execute following command to update systemd units generated from this file.

# systemctl daemon-reload

Mount all entries in /etc/fstab using mount command.

# mount -a

Verify that our Stratis filesystem are mounted correctly.

# mount | grep /dev/mapper/stratis
/dev/mapper/stratis-1-c943c04939f5432cbe4d3d9985cd462e-thin-fs-d62f6884dffc40a6b8024784b7f60ca8 on /mnt/prod type xfs (rw,relatime,seclabel,attr2,inode64,sunit=2048,swidth=2048,noquota,x-systemd.requires=stratisd.service)
/dev/mapper/stratis-1-c943c04939f5432cbe4d3d9985cd462e-thin-fs-9ce32861f56b408597550d88e9bf5a44 on /mnt/test type xfs (rw,relatime,seclabel,attr2,inode64,sunit=2048,swidth=2048,noquota,x-systemd.requires=stratisd.service)

Create Snapshot of Stratis FileSystems

Copy some data in /mnt/prod directory.

# cp -r /etc/[a-f]* /mnt/prod

We can take snapshot of the prod_db_fs filesystem using following command.

# stratis fs snapshot db_pool prod_db_fs prod_db_bkp_17dev2019

Check Stratis filesystems.

# stratis fs list
Pool Name  Name                   Used     Created            Device                                  UUID
db_pool    prod_db_bkp_17dev2019  577 MiB  Dec 17 2019 23:28  /stratis/db_pool/prod_db_bkp_17dev2019  b4583769df9e40d790a55f11b705b65d
db_pool    prod_db_fs             577 MiB  Dec 17 2019 22:22  /stratis/db_pool/prod_db_fs             d62f6884dffc40a6b8024784b7f60ca8
db_pool    test_db_fs             546 MiB  Dec 17 2019 22:22  /stratis/db_pool/test_db_fs             9ce32861f56b408597550d88e9bf5a44

A Stratis Snapshot is also a Stratis filesystem, therefore, we can mount it inplace of the actual filesystem to restore a previous state of data, without required to remove the existing filesystem.

Remove a Stratis FileSystem

To remove a filesystem, make sure it is not mounted and then remove it using following command.

# umount /mnt/test
# stratis fs destroy db_pool test_db_pool

Remove a Stratis Storage Pool

To remove a Stratis Storage, make sure that, there isn’t any filesystem exists within that pool.

Remove an existing storage pool using following command.

# stratis pool destroy backup_pool

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Conclusion

We have successfully installed and configured Stratis local storage on CentOS 8 and explored some of it’s advanced features like thin-provisioning and snapshots.

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