Persistent Mounts
Before we go to mounting the disks persistently, we need to know about these two things:
- Non-Superuser Mounts
- UUID
Non-Superuser Mounts
Normally, only the superuser can mount filesystems. However, when fstab contains the user option on a line, anybody can mount the corresponding system. By default, only the user that mounted a filesystem can unmount it.
Reference: ~Non-Superuser Mounts
UUID
This is the Universally Unique Identifier. Similar to a MAC address, it is a way to identify the correct drive even if the drive letter or partition number changes. This is automatically created anytime a filesystem is added to the system.
To see the UUIDs associated with our drives:
$ ll /dev/disk
total 0
drwxr-xr-x. 2 root root 220 Dec 6 08:38 by-partuuid
drwxr-xr-x. 2 root root 140 Dec 6 09:19 by-uuid
$ ll /dev/disk/by-uuid/
total 0
lrwxrwxrwx. 1 root root 11 Dec 6 08:40 52545136-5e0e-4022-86c0-7845250d5263 -> ../../xvdc1
lrwxrwxrwx. 1 root root 11 Dec 6 08:41 7d123d52-b4c3-4a03-b077-c03761f57d0e -> ../../xvdc2
lrwxrwxrwx. 1 root root 10 Dec 6 08:36 b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e -> ../../xvdb
lrwxrwxrwx. 1 root root 11 Dec 6 09:19 b8c13319-646e-4933-87e0-27bf530e04ec -> ../../xvdc3
lrwxrwxrwx. 1 root root 11 Dec 6 08:04 d35fe619-1d06-4ace-9fe3-169baad3e421 -> ../../xvda2
Another command to see the UUIDs:
# Note that the IDs may now be different since I added this part on a much later date.
[root@tst-rhel ~]# blkid
/dev/xvda2: UUID="d35fe619-1d06-4ace-9fe3-169baad3e421" BLOCK_SIZE="512" TYPE="xfs" PARTUUID="25a742d0-6b18-4c26-951a-2b99f1be934d"
/dev/xvdc1: UUID="d6eaa147-9986-4af3-bd28-f776b4628643" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="dc5fac76-01"
/dev/xvda1: PARTUUID="07c6574c-7f85-4859-9689-c8090f35545a"
/dev/xvdb1: UUID="d3e1da6b-5577-4d21-8f78-af81b31246c6" BLOCK_SIZE="512" TYPE="xfs" PARTLABEL="one" PARTUUID="56ffe2f0-90c9-4555-9d0d-49c63b2c8192"
## Labeling using tune2fs
Besides getting the specific UUID of the partitions, we can also assign labels to them and we can refer to this labels. To do this, we can use the **tune2fs** utility.
```bash
[root@tst-rhel ~]# tune2fs --help
tune2fs 1.45.6 (20-Mar-2020)
tune2fs: invalid option -- '-'
Usage: tune2fs [-c max_mounts_count] [-e errors_behavior] [-f] [-g group]
[-i interval[d|m|w]] [-j] [-J journal_options] [-l]
[-m reserved_blocks_percent] [-o [^]mount_options[,...]]
[-r reserved_blocks_count] [-u user] [-C mount_count]
[-L volume_label] [-M last_mounted_dir]
[-O [^]feature[,...]] [-Q quota_options]
[-E extended-option[,...]] [-T last_check_time] [-U UUID]
[-I new_inode_size] [-z undo_file] device
Note that tune2fs can only be used for ext2, ext3, and ext4 file types. For XFS types, tune2fs cannot be interpreted. When tune2fs is used on a xfs, it will return an error:
Bad magic number in super-block
This simply means that tune2fs doesn't understand the filesystem type. As an example, we have /dev/xvdb1 which we set to xfs filesystem.
[root@tst-rhel ~]# blkid | grep xvdb
/dev/xvdb1: UUID="8371f83f-8715-4e38-a3c9-fde7d10a7c97" BLOCK_SIZE="4096" TYPE="ext4" PARTLABEL="one" PARTUUID="56ffe2f0-90c9-4555-9d0d-49c63b2c8192"
[root@tst-rhel ~]# mkfs.xfs /dev/xvdb1
mkfs.xfs: /dev/xvdb1 appears to contain an existing filesystem (ext4).
mkfs.xfs: Use the -f option to force overwrite.
[root@tst-rhel ~]# mkfs.xfs /dev/xvdb1 -f
meta-data=/dev/xvdb1 isize=512 agcount=4, agsize=65472 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=261888, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=1566, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@tst-rhel ~]# blkid | grep xvdb
/dev/xvdb1: UUID="69e31de4-d231-4b80-9fcb-40ee1aef0150" BLOCK_SIZE="512" TYPE="xfs" PARTLABEL="one" PARTUUID="56ffe2f0-90c9-4555-9d0d-49c63b2c8192"
[root@tst-rhel ~]# tune2fs -L "Section-B" /dev/xvdb1
tune2fs 1.45.6 (20-Mar-2020)
tune2fs: Bad magic number in super-block while trying to open /dev/xvdb1
/dev/xvdb1 contains a xfs file system
Because of this, we'll need to change the filesystem to Ext4 and retry tune2fs again.
[root@tst-rhel ~]# blkid | grep xvdb
/dev/xvdb1: UUID="69e31de4-d231-4b80-9fcb-40ee1aef0150" BLOCK_SIZE="512" TYPE="xfs" PARTLABEL="one" PARTUUID="56ffe2f0-90c9-4555-9d0d-49c63b2c8192"
[root@tst-rhel ~]# mkfs.ext4 /dev/xvdb1
mke2fs 1.45.6 (20-Mar-2020)
/dev/xvdb1 contains a xfs file system
Proceed anyway? (y,N) y
Creating filesystem with 261888 4k blocks and 65536 inodes
Filesystem UUID: 53120174-378d-4db6-978b-d672660e2b06
Superblock backups stored on blocks:
32768, 98304, 163840, 229376
Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done
[root@tst-rhel ~]# blkid | grep xvdb
/dev/xvdb1: UUID="53120174-378d-4db6-978b-d672660e2b06" BLOCK_SIZE="4096" TYPE="ext4" PARTLABEL="one" PARTUUID="56ffe2f0-90c9-4555-9d0d-49c63b2c8192"
Retrying tune2fs again:
[root@tst-rhel ~]# tune2fs -L 'Section-B' /dev/xvdb1
tune2fs 1.45.6 (20-Mar-2020)
[root@tst-rhel ~]# blkid | grep xvdb
/dev/xvdb1: LABEL="Section-B" UUID="53120174-378d-4db6-978b-d672660e2b06" BLOCK_SIZE="4096" TYPE="ext4" PARTLABEL="one" PARTUUID="56ffe2f0-90c9-4555-9d0d-49c63b2c8192"
We can now use the label in fstab to refer to this partition.
[root@tst-rhel ~]# vim /etc/fstab
UUID=d35fe619-1d06-4ace-9fe3-169baad3e421 / xfs defaults 0 0
UUID=e6bcc068-628c-4555-b06e-9cda9563cf8c swap swap defaults 0 0
LABEL=Section-B /mnt/diskb1 xfs defaults 0 0
When we run the mount command again, the system will go through the /etc/fstab and it will see the new entry for /mnt/diskb1 which is pointing to the newly created label.
[root@tst-rhel ~]# mount | grep diskb1
[root@tst-rhel ~]# mount -a
[root@tst-rhel ~]# mount | grep diskb1
/dev/xvdb1 on /mnt/diskb1 type ext4 (rw,relatime,seclabel)
Persistently mount filesystems
In the previous sections, we did a manual mounting of partitions. To automatically mount them during system start, we specify the partitions and their respective mountpoints in the /etc/fstab file. The entries in this file is used by the systemd-fstab-generator utility to generate the systemd mounts. To update it, make sure to use systemctl daemon-reload after diting the /etc/fstab file.
$ vi /etc/fstab
UUID=d35fe619-1d06-4ace-9fe3-169baad3e421 / xfs defaults 0 0
As an example, we can mount '/dev/xvdb1' on bootup by adding its UUID and the mountpoint to the fstab.
$ ll /dev/disk/by-uuid/
total 0
lrwxrwxrwx. 1 root root 11 Dec 6 08:40 52545136-5e0e-4022-86c0-7845250d5263 -> ../../xvdc1
lrwxrwxrwx. 1 root root 11 Dec 6 08:41 7d123d52-b4c3-4a03-b077-c03761f57d0e -> ../../xvdc2
lrwxrwxrwx. 1 root root 10 Dec 6 08:36 b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e -> ../../xvdb
lrwxrwxrwx. 1 root root 11 Dec 6 09:19 b8c13319-646e-4933-87e0-27bf530e04ec -> ../../xvdc3
lrwxrwxrwx. 1 root root 11 Dec 6 08:04 d35fe619-1d06-4ace-9fe3-169baad3e421 -> ../../xvda2
From the output above, we can see that /dev/xvdb1 has a UUID=b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e. Add this to the /etc/fstab and indicate EXT4 as the filesystem.
$ sudo vi /etc/fstab
UUID=d35fe619-1d06-4ace-9fe3-169baad3e421 / xfs defaults 0 0
# EDEN: Mount /dev/xvdb1 during bootup
UUID=b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e /mnt/diskb1 ext4 defaults 1 1
Before we test this, we check again the block devices:
$ lsblk -f
NAME FSTYPE LABEL UUID MOUNTPOINT
xvda
├─xvda1
└─xvda2 xfs d35fe619-1d06-4ace-9fe3-169baad3e421 /
xvdb ext4 b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e /mnt/diskb1
xvdc
├─xvdc1 ext3 52545136-5e0e-4022-86c0-7845250d5263 /mnt/diskc1
├─xvdc2 ext3 7d123d52-b4c3-4a03-b077-c03761f57d0e /mnt/diskc2
└─xvdc3 ext3 b8c13319-646e-4933-87e0-27bf530e04ec /mnt/diskc3
Restart
As mentioned in the previous sections, we can use the mount command to mount the disks during runtime. This is also the recommended way because if there are issues in the /etc/fstab, we can immediately catch the error after running the mount command.
But since we only added one entry in the /etc/fstab file, we'll proceed with the reboot. After restarting the instance, we see that all the mounted partitions are removed except for xvdb.
sudo reboot
$ lsblk -f
NAME FSTYPE LABEL UUID MOUNTPOINT
xvda
├─xvda1
└─xvda2 xfs d35fe619-1d06-4ace-9fe3-169baad3e421 /
xvdb ext4 b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e /mnt/diskb1
xvdc
├─xvdc1 ext3 52545136-5e0e-4022-86c0-7845250d5263
├─xvdc2 ext3 7d123d52-b4c3-4a03-b077-c03761f57d0e
└─xvdc3 ext3 b8c13319-646e-4933-87e0-27bf530e04ec
mount -a
We now know that the entry in /etc/fstab works. Let's now add the other partitions.
$ ll /dev/disk/
total 0
drwxr-xr-x. 2 root root 220 Dec 6 11:05 by-partuuid
drwxr-xr-x. 2 root root 140 Dec 6 11:05 by-uuid
$ ll /dev/disk/by-uuid/
total 0
lrwxrwxrwx. 1 root root 11 Dec 6 11:05 52545136-5e0e-4022-86c0-7845250d5263 -> ../../xvdc1
lrwxrwxrwx. 1 root root 11 Dec 6 11:05 7d123d52-b4c3-4a03-b077-c03761f57d0e -> ../../xvdc2
lrwxrwxrwx. 1 root root 10 Dec 6 11:05 b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e -> ../../xvdb
lrwxrwxrwx. 1 root root 11 Dec 6 11:05 b8c13319-646e-4933-87e0-27bf530e04ec -> ../../xvdc3
lrwxrwxrwx. 1 root root 11 Dec 6 11:05 d35fe619-1d06-4ace-9fe3-169baad3e421 -> ../../xvda2
$ sudo vi /etc/fstab
UUID=d35fe619-1d06-4ace-9fe3-169baad3e421 / xfs defaults 0 0
UUID=b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e /mnt/diskb1 ext4 defaults 1 1
UUID=52545136-5e0e-4022-86c0-7845250d5263 /mnt/diskc1 ext3 defaults 1 1
UUID=7d123d52-b4c3-4a03-b077-c03761f57d0e /mnt/diskc2 ext3 defaults 1 1
UUID=b8c13319-646e-4933-87e0-27bf530e04ec /mnt/diskc3 ext3 defaults 1 1
Before we test again, make sure only one disk is mounted.
$ lsblk -f
NAME FSTYPE LABEL UUID MOUNTPOINT
xvda
├─xvda1
└─xvda2 xfs d35fe619-1d06-4ace-9fe3-169baad3e421 /
xvdb ext4 b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e /mnt/diskb1
xvdc
├─xvdc1 ext3 52545136-5e0e-4022-86c0-7845250d5263
├─xvdc2 ext3 7d123d52-b4c3-4a03-b077-c03761f57d0e
└─xvdc3 ext3 b8c13319-646e-4933-87e0-27bf530e04ec
This time, run the mount -a command and verify. This will scan the /etc/fstab and mount all filesystems for us instead of us manually mounting each partition. This is also especially useful when you cannot restart the server and you need to mount new disks.
sudo mount -a
$ lsblk -f
NAME FSTYPE LABEL UUID MOUNTPOINT
xvda
├─xvda1
└─xvda2 xfs d35fe619-1d06-4ace-9fe3-169baad3e421 /
xvdb ext4 b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e /mnt/diskb1
xvdc
├─xvdc1 ext3 52545136-5e0e-4022-86c0-7845250d5263 /mnt/diskc1
├─xvdc2 ext3 7d123d52-b4c3-4a03-b077-c03761f57d0e /mnt/diskc2
└─xvdc3 ext3 b8c13319-646e-4933-87e0-27bf530e04ec /mnt/diskc3
This works. Now unmount the four partitions and verify that nothing is mounted.
sudo umount /mnt/diskb1
sudo umount /mnt/diskc1
sudo umount /mnt/diskc2
sudo umount /mnt/diskc3
$ lsblk -f
NAME FSTYPE LABEL UUID MOUNTPOINT
xvda
├─xvda1
└─xvda2 xfs d35fe619-1d06-4ace-9fe3-169baad3e421 /
xvdb ext4 b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e
xvdc
├─xvdc1 ext3 52545136-5e0e-4022-86c0-7845250d5263
├─xvdc2 ext3 7d123d52-b4c3-4a03-b077-c03761f57d0e
└─xvdc3 ext3 b8c13319-646e-4933-87e0-27bf530e04ec
Restart the instance once again and see if all the partitions are automatically mounted during bootup. This last step is optional. We just want to demonstrate here that if mount -a worked with no errors, then we shouldn't have any issues restarting the server.
sudo reboot
$ df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 7.7G 0 7.7G 0% /dev
tmpfs 7.8G 0 7.8G 0% /dev/shm
tmpfs 7.8G 17M 7.8G 1% /run
tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup
/dev/xvda2 10G 2.8G 7.3G 28% /
/dev/xvdb 98G 61M 93G 1% /mnt/diskb1
/dev/xvdc3 34G 49M 32G 1% /mnt/diskc3
/dev/xvdc1 33G 49M 31G 1% /mnt/diskc1
/dev/xvdc2 33G 49M 31G 1% /mnt/diskc2
tmpfs 1.6G 0 1.6G 0% /run/user/1000
$ lsblk -f
NAME FSTYPE LABEL UUID MOUNTPOINT
xvda
├─xvda1
└─xvda2 xfs d35fe619-1d06-4ace-9fe3-169baad3e421 /
xvdb ext4 b3475d34-e9cb-4e8e-9ace-a1fdf7ed508e /mnt/diskb1
xvdc
├─xvdc1 ext3 52545136-5e0e-4022-86c0-7845250d5263 /mnt/diskc1
├─xvdc2 ext3 7d123d52-b4c3-4a03-b077-c03761f57d0e /mnt/diskc2
└─xvdc3 ext3 b8c13319-646e-4933-87e0-27bf530e04ec /mnt/diskc3
Systemd Mounts
Systemd provides a mechanism for managing filesystem mounts through systemd mount units. These units are configurations that specify how and where a filesystem should be mounted during the system boot process or on demand. Systemd mount units offer a more flexible options for handling dependencies, automounting, and monitoring. They are particularly useful in environments where dynamic management of mounts is required, such as with network filesystems or removable media.
/etc/fstabmounts already are systemd mounts.- Mount can be created using systemd .mount files.
- Using .mount files allow you to be more specific in defining dependencies.
- Use
systemctl cat tmp.mountfor an example.
Systemd mount units
Here's an example of how you can define a systemd mount unit:
[root@tst-rhel ~]# systemctl cat tmp.mount
[Unit]
Description=Temporary Directory (/tmp)
Documentation=man:hier(7)
Documentation=https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
ConditionPathIsSymbolicLink=!/tmp
DefaultDependencies=no
Conflicts=umount.target
Before=local-fs.target umount.target
After=swap.target
[Mount]
What=tmpfs
Where=/tmp
Type=tmpfs
Options=mode=1777,strictatime,nosuid,nodev
# Make 'systemctl enable tmp.mount' work:
[Install]
WantedBy=local-fs.target
Check the status:
[root@tst-rhel ~]# systemctl status tmp.mount
● tmp.mount - Temporary Directory (/tmp)
Loaded: loaded (/usr/lib/systemd/system/tmp.mount; disabled; vendor preset: disabled)
Active: inactive (dead)
Where: /tmp
What: tmpfs
Docs: man:hier(7)
https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
Enable it:
[root@tst-rhel ~]# systemctl enable --now tmp.mount
Created symlink /etc/systemd/system/local-fs.target.wants/tmp.mount → /usr/lib/systemd/system/tmp.mount.
Checking the status again, we see that the tmp.mount is mounted using systemd:
[root@tst-rhel ~]# systemctl status tmp.mount
● tmp.mount - Temporary Directory (/tmp)
Loaded: loaded (/usr/lib/systemd/system/tmp.mount; enabled; vendor preset: disabled)
Active: active (mounted) since Fri 2021-12-31 00:02:29 +08; 2min 24s ago
Where: /tmp
What: tmpfs
Docs: man:hier(7)
https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
Tasks: 0 (limit: 100840)
Memory: 4.0K
CGroup: /system.slice/tmp.mount
Dec 31 00:02:29 tst-rhel systemd[1]: Mounting Temporary Directory (/tmp)...
Dec 31 00:02:29 tst-rhel systemd[1]: Mounted Temporary Directory (/tmp).
We can also confirm that the tmp.mount is mounted by running the mount command:
[root@tst-rhel ~]# mount | grep tmp
devtmpfs on /dev type devtmpfs (rw,nosuid,seclabel,size=8067292k,nr_inodes=2016823,mode=755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,seclabel)
tmpfs on /run type tmpfs (rw,nosuid,nodev,seclabel,mode=755)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,seclabel,mode=755)
tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,seclabel,size=1620980k,mode=700,uid=1000,gid=1000)
tmpfs on /tmp type tmpfs (rw,nosuid,nodev,seclabel)
Mounting a partition
Now that we understand how systemd mount works, we'll unmount /dev/xvdb1 and remove it's entry in /etc/fstab.
[root@tst-rhel ~]# lsblk -a
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 50G 0 disk
├─xvda1 202:1 0 1M 0 part
└─xvda2 202:2 0 50G 0 part /
xvdb 202:16 0 5G 0 disk
└─xvdb1 202:17 0 1023M 0 part /mnt/diskb1
xvdc 202:32 0 25G 0 disk
└─xvdc1 202:33 0 25G 0 part
Unmount the partition and verify that it's removed.
[root@tst-rhel ~]# umount /mnt/diskb1
[root@tst-rhel ~]# lsblk -a
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 50G 0 disk
├─xvda1 202:1 0 1M 0 part
└─xvda2 202:2 0 50G 0 part /
xvdb 202:16 0 5G 0 disk
└─xvdb1 202:17 0 1023M 0 part
xvdc 202:32 0 25G 0 disk
└─xvdc1 202:33 0 25G 0 part
Remove the entry from /etc/fstab:
[root@tst-rhel ~]# vim /etc/fstab
UUID=d35fe619-1d06-4ace-9fe3-169baad3e421 / xfs defaults 0 0
UUID=e6bcc068-628c-4555-b06e-9cda9563cf8c swap swap defaults 0 0
Create a mount file for /dev/xvdb1 by simply copying the existing tmp.mount to the appropriate directory /etc/systemd/system/ and editing it. Notice that we named the mount file mnt-diskb1.mount. This is because the mount point is /mnt/diskb1. If mount point is only diskb1, then the mount file should be diskb1.mount.
cp /usr/lib/systemd/system/tmp.mount /etc/systemd/system/mnt-diskb1.mount
[root@tst-rhel ~]# vim /etc/systemd/system/mnt-diskb1.mount
[Unit]
Description=Section B
Documentation=man:hier(7)
Conflicts=umount.target
Before=local-fs.target umount.target
[Mount]
What=LABEL='Section-B'
Where=/mnt/diskb1
Type=ext4
Options=defaults
# Make 'systemctl enable tmp.mount' work:
[Install]
WantedBy=local-fs.target
Afterwards, reload the daemon and then check the status. Notice in the Loaded line, it uses the mount file:
[root@tst-rhel ~]# systemctl daemon-reload
[root@tst-rhel ~]# systemctl status mnt-diskb1.mount
● mnt-diskb1.mount - Section B
Loaded: loaded (/etc/systemd/system/mnt-diskb1.mount; static; vendor preset: disabled)
Active: inactive (dead)
Where: /mnt/diskb1
What: LABEL='Section-B'
Docs: man:hier(7)
Dec 30 23:31:20 tst-rhel systemd[1]: mnt-diskb1.mount: Succeeded.
Dec 30 23:46:24 tst-rhel systemd[1]: mnt-diskb1.mount: Succeeded.
Dec 31 00:08:41 tst-rhel systemd[1]: mnt-diskb1.mount: Succeeded.
Enable the unit. Disregard the warning message for now. Check the status again.
[root@tst-rhel ~]# systemctl enable --now mnt-diskb1.mount
The unit files have no installation config (WantedBy, RequiredBy, Also, Alias
settings in the [Install] section, and DefaultInstance for template units).
This means they are not meant to be enabled using systemctl.
Possible reasons for having this kind of units are:
1) A unit may be statically enabled by being symlinked from another unit's
.wants/ or .requires/ directory.
2) A unit's purpose may be to act as a helper for some other unit which has
a requirement dependency on it.
3) A unit may be started when needed via activation (socket, path, timer,
D-Bus, udev, scripted systemctl call, ...).
4) In case of template units, the unit is meant to be enabled with some
instance name specified.
[root@tst-rhel ~]# systemctl status mnt-diskb1.mount
● mnt-diskb1.mount - Section B
Loaded: loaded (/etc/systemd/system/mnt-diskb1.mount; static; vendor preset: disabled)
Active: active (mounted) since Fri 2021-12-31 00:33:38 +08; 13s ago
Where: /mnt/diskb1
What: /dev/xvdb1
Docs: man:hier(7)
Tasks: 0 (limit: 100840)
Memory: 32.0K
CGroup: /system.slice/mnt-diskb1.mount
Dec 31 00:33:37 tst-rhel systemd[1]: Mounting Section B...
Dec 31 00:33:38 tst-rhel systemd[1]: Mounted Section B.