Disks & Storage

Where to find it

Open a server's Overview. Below the CPU, Memory, Network and Disk cards is Disks & Storage: Physical disks, partitions and mount points. The data is read from lsblk and df, and the time of the last read is shown next to the refresh button. On a server with more than one disk, the Disk card also shows how many disks there are and how many are not mounted.

Reading the list

The totals at the top count disks, the total size, how many are mounted and how many are not mounted. Each physical disk gets its own group, with its partitions and mount points underneath and a usage bar for every mounted filesystem. The root disk comes first, then other mounted disks, then disks with nothing mounted.

Network shares, bind mounts and other virtual mounts that belong to no disk are listed under Other filesystems. Pseudo filesystems such as tmpfs, overlay, squashfs and snap loop devices are hidden. The footer says how many, with Show to list them and Hide to put them away again.

Mount a disk

A disk with nothing mounted shows Not mounted, with Mount… and Ignore.

1. Choose Mount… to open Mount {disk}
2. Pick the Partition if the disk has more than one
3. Set the Mount path. The default is /mnt/ followed by the device name, and the folder is created if it does not exist
4. Leave Add to /etc/fstab (UUID, nofail) on if the mount should survive a reboot
5. Choose Mount

With the fstab option on, Server Compass backs up /etc/fstab to /etc/fstab.servercompass.bak first, then adds a line that references the volume by UUID with the nofail option. If the volume is ever detached, the server still boots instead of stopping in emergency mode.

Formatting a blank disk

If the device has no filesystem, the dialog says No filesystem detected — formatting erases the device, and offers Format as with ext4 (recommended) or xfs. Type the device name (for example vdb1) to confirm, then choose Format and mount. A device that already has a filesystem is never offered a format. Mount it as it is.

What Server Compass refuses to do

To protect your data, mounting is refused when:

• the disk holds the root or boot filesystem
• the device is already mounted somewhere
• the mount path is a folder that is not empty, because mounting there would hide what is in it
• a format is requested for a device that already has a filesystem

Ignore a disk

Ignore marks a disk you do not plan to use. It stops counting as not mounted and the prompt to mount it goes away. Un-ignore brings it back.

Alerts and history for other filesystems

A Disk Usage alert rule has a Filesystem field. Leave it on Root (/), or pick any mounted filesystem, such as /mnt/data, to be warned before a data volume fills up. See Setting Up Monitoring.

In Metrics History, when the stored samples cover more than one filesystem, the Disk picker chooses which filesystem the Disk column shows.

What runs on the server

Disks & Storage reads the disk inventory with lsblk and usage with df. Mounting checks the path with findmnt, creates the folder with mkdir -p, and runs mount. Formatting first checks the device with blkid, then runs mkfs.ext4 or mkfs.xfs. The fstab entry is written only after backing up the file, and systemd is reloaded so it sees the new mount.