LVM snapshots: what actually happens?

The quick answer

A classic LVM snapshot preserves a point-in-time view while the origin volume continues changing.

lvcreate -s -n snap -L 2G vg/data

What's going on?

A classic LVM snapshot preserves a point-in-time view while the origin volume continues changing.

Understanding the underlying mechanism makes troubleshooting much easier than memorising a command in isolation.

Dig a little deeper

Snapshots are not backups: they share failure domains with their origin. Monitor snapshot usage and test restoration. Thin snapshots behave differently from classic snapshots.

Hands-on commands

Try these in a suitable test environment. Read each command before running it, especially if you have elevated privileges.

sudo lvs -a -o lv_name,origin,lv_size,data_percent
# Use a disposable lab VG before creating snapshots