[linux-lvm] meaning of -L for snapshots ?

[Jonathan Brassow]

Note, that if you guess wrong and create a snapshot that is too small,
you can always grow the volume (lvextend).

 brassow

On Mon, 2005-12-19 at 16:49 -0800, kelsey hudson wrote:
> 
> Olivier Kaloudoff wrote:
> 
> >     Who can explain the usage of -L10M for my snapshot ?
> 
> LVM snapshots have a limitation to how much data can change before the 
> snapshot becomes invalid. So, by using -L10M, you're saying to keep the 
> snapshot around until 10M of data has changed, then the snapshot becomes 
> invalid.
> 
> Because of the way LVM snapshots work, they require extra space on a 
> volume. So, the size of your snapshot volume dictates how long it will 
> remain valid. A good rule of thumb is between 10% and 20% of your 
> primary volume's size. That way, 10 to 20% of the filesystem's contents 
> can change and your snapshot will remain valid.
> 
> Hope this clears some things up for you.
> 
> -Kelsey
> 
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