[lug] LVM and disk failure

[Jeffrey Siegal]

On Jan 8, 2006, at 11:00 , Daniel Webb wrote:

> In the case I have in mind, I'm thinking of user accounts that  
> should be
> resizable.  I think a better way will be to create a new logical  
> volume and
> filesystem for each user, instead of putting all users on the same  
> filesystem.
> Then at worst those users whose logical volumes cross a physical  
> boundary are
> twice as likely to lose their filesystem, but that's not nearly as  
> bad as the
> risk of doing it all on one filesystem across many physical drives.

You don't really need LVM for this at all.  You can just split up  
your user accounts across multiple physical devices (or RAID sets).   
Of course, LVM adds some value in that you can more easily move user  
accounts around if need be, including during normal operations.

If you do use LVM this way, note that there is no guarantee that a LV  
won't be spread across multiple PVs (not just two), if that's where  
the space is available when its created.  You can assign LVs to  
specific PVs within a volume, but it takes extra effort.