Re: Dynamic LVM resizing daemon?

[Ronny Aasen <list@datapart-as.no>]

On Sun, 2006-09-17 at 23:40 +0200, Petter Reinholdtsen wrote:
> Now that ext3, lvm and the linux kernel support file system resizes
> without umounting, perhaps it is time to create something that
> dynamically increases the file system sizes when they fill up, based
> on some rules.
> 
> For example, /var/ could be increased by 2% every time it is 95% full,
> until it reaches 10 GiB, or /var/opt/ltsp/swapfiles/ could be
> increased by 128 MiB every time there is less than 64 MiB left, until
> it occupies 10% of the LVM volume group.  Every time it resizes a file
> system, the sysadmin should get some notification.
> 
> I suspect this should be possible to implement in some script
> language.  Anyone know if a similar system already exist?  If we had
> such system, the need to manually adjust the file system sizes should
> be drastically reduced.

sounds like a job for  cfengine.
one could do everything from cfengine, but it would be easier to do some
proper error checknig in a script. and one must run cfengine from cron,
something i feel we should work towards anyway. 


untested example full of typoes and logical faults. 
--------
cf.checkspace

disks:
    debian.!woody.!sarge.server::
         #/filesystem freespace=size-limit define=class-list(,:.) 
         /var/opt/swapfiles freespace=64mb define=needmoreswap


shellcomands:
    debian.!woody.!sarge.server.needmoreswap::
          "moreswap.sh"


------
moreswap.sh

#!/bin/sh
if [ mountpoint -q /var/opt/swapfiles ] ; then
   partition=$(mount | grep /var/opt/swapfiles | cut -d" " -f1)
   lvresize -L +128M $partition  && resize2fs $partition
fi