Hands-on Lab·Red Hat Certified System Administrator
LVM Logical Volumes
The top LVM layer and the one you actually put a filesystem on. Both ways of specifying size are used here, including the percentage forms that save arithmetic under time pressure, and the rounding LVM performs is shown announcing itself.
Local Storage Guide 34 of 67 Intermediate
- OSRHEL 10.0 (Coughlan)
- Kernel6.12.0-55.9.1.el10_0
- dnf4.20.0
- Flatpak1.16.0
- TimeAbout 12 min
- Reviewed23 August 2026
Written against the versions above. A logical volume appears under two paths: `/dev/<vg>/<lv>` and `/dev/mapper/<vg>-<lv>`. Both are symlinks to the same `/dev/dm-N`. Either works in `/etc/fstab`, though a UUID is better still - see {{guide:mounting-by-uuid-and-label}}.
| Server Name | IP Address | OS | Roles | CPU | RAM | HDD |
|---|---|---|---|---|---|---|
| RHCSA-A01 | 192.168.0.31 | RHEL 10.0 (Coughlan) | Practice node (graded) - spare /dev/sda | 2 Core | 4 GB | 50 GB + 15 GB |
Before you start
- A volume group with free space -
guide 33builds one. - Every destructive command on this page names a
/dev/sdadevice. On this machine the operating system is entirely on/dev/sdb. Check yours before running anything here - the first step shows how.
-
Creating them
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Where the device appears
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Two ways to say how big, and the rounding
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Removing them