Resizing logical volumes

[Philip Prindeville]

Paul Howarth wrote:

>On Tue, 2006-05-16 at 23:15 +0200, Aad Rijnberg wrote: 
>  
>
>>I have installed FC5 using LVM. During installation I chose the /usr volume 
>>apparently too small, because now there is not enough room to install 
>>updates.
>>    
>>
>
>Before changing volume sizes, another option you might want to consider
>is to remove a few large packages that you don't use. Doing this will
>also have the advantage that you don't need to download and install
>updates for these large packages if they appear.
>
>You can get a list of installed packages sorted by size like this:
>
>$ rpm -qa --qf '%{SIZE}\t%{NAME}\n' | sort -n
>
>You can then use "rpm -qi packagename" to get information about what a
>particular package is if you don't know it, and "rpm -e packagename" (as
>root) to get rid of it if you decide you don't want it. rpm will tell
>you if there are other packages that depend on the one you're trying to
>remove, and refuse to remove the package.
>
>  
>
>>To solve this problem, I would like to decrease my /home volume (LogVol03) by 
>>some 3GB and increase the /usr volume (LogVol01) by the same amount. /home 
>>physically resides on /dev/hda2 whereas /usr resides on /dev/hda3.
>>    
>>
>
>The physical location of the volumes does not matter if they are in the
>same volume group. In fact, how do you know where they are?
>
>  
>
>>I was thinking of using system-config-lvm for this. Is that a good idea?
>>    
>>
>
>I don't know, I've never used it.
>
>  
>
>>Can this whole operation be executed without data loss?
>>    
>>
>
>Yes.
>
>  
>
>>It is possible to execute 
>>system-config-lvm while the partitions are mounted?
>>    
>>
>
>It's not possible to run it when they're not mounted, since
>system-config-lvm lives under /usr :-)
>
>I usually do this using the command-line tools. The general flow would
>be:
>
>1. Reduce the size of the /home filesystem by *more* than the amount you
>eventually want to reduce it by (say 4G). This avoids the possibility
>that due to rounding issues your filesystem may extend past the end of
>the logical volume it's on when the logical volume is shrunk. You may be
>able to do this online using ext2online. If it says it can't do it,
>you'll need to go to single user mode, unmount /home and /usr, and use
>resize2fs instead (and for the following steps too)
>
>2. Reduce the size of LogVol03 by 3G, using lvreduce.
>
>3. Resize /home to fill the logical volume it's on, again using
>ext2online or resize2fs. By not specifying the size to use, the tool
>will expand the filesystem to fill the volume.
>
>4. Increase the size of LogVol01 by 3GB using lvextend.
>
>5. Resize /usr to fill he logical volume it's on, again using ext2online
>or resize2fs. By not specifying the size to use, the tool will expand
>the filesystem to fill the volume.
>
>Paul.
>
>  
>

Ok.. now what if they are on different volume groups and partitions? ;-)

-Philip