Naming Conventions
In Linux, hardware devices are typically represented by special device files in the /dev directory with names such as sda and sdb. Subdirectories within /dev/disk contain symbolic links with more descriptive names, to make it easier to identify devices.
/dev/sd* names may change between reboots, so we recommend using the links in /dev/disk/by-id for centron volumes (and all partitions on them), as they remain predictable and reliable across reboots.
Links to /dev/disk/by-id
Links in the //dev/disk/by-id subdirectory are usually associated with hardware serial numbers, but the //dev/disk/by-id identifiers for centron volumes are generally made up of the following parts:
-
The string
scsi-0DO_Volume_ -
The name of the volume, such as
volume-nyc1-01 -
The partition suffix, such as
-part1, if the volume is partitioned
The full identifier for a volume called volume-nyc1-01 would be /dev/disk/by-id/scsi-0DO_Volume_volume-nyc1-01. The first partition on this volume would be /dev/disk/by-id/scsi-0DO_Volume_volume-nyc1-01-part1.
Automatic integration
| Volume name | Automatic mount point | Mount unit file |
|---|---|---|
| example | /mnt/example | /etc/systemd/system/mnt-example.mount |
| sc01c | /mnt/volume_nyc_01 | /etc/systemd/system/mnt-volume_nyc_01.mount |
Unit files
When you create a new volume, you can format it automatically and mount it to ccloud³ VMs running supported operating systems. Automatic mounting uses systemd on distributions that support it.
The systemd mount unit files are named /etc/systemd/system/pfad-zum-einbindungspunkt.mount. The path to the integration point uses hyphens as separators instead of slashes.
Integration points
We automatically mount disks in /mnt within a directory bearing the same name as the volume, so that a volume named example would have the mount point /mnt/example.
However, due to the naming convention of the systemd mount unit file, we cannot automatically mount a volume on a path that contains hyphens. If there are hyphens in the volume name, we replace the hyphens with underscores, so that a volume named volume-nyc-01 would have the mount point /mnt/volume_nyc_01.
To ensure consistency, we are also adapting this behaviour for distributions other than systemd.