How can I check the LVM mirroring under Linux? E.g.: are there any mirrors on a given machine & some details about them, etc.
lvs | fgrep "mwi"
"m" means: mirrored
lvdisplay will show you the configured physical volumes, volume groups and logical volumes respectively of the LVM subsystem on a machine.
mdadm will give you information about the configured raid subsystem.
You can use this too:
cat /proc/mdstat Personalities : unused devices: <none>
It means you don't have mirror or any RAID configuration in your system.