Things to do this week instead of arguing about mixers

[Florian Festi]

Michael Cronenworth wrote:
> -------- Original Message --------
> Subject: Re: Things to do this week instead of arguing about mixers
> From: Eric Sandeen <sandeen at redhat.com>
> To: Development discussions related to Fedora 
> <fedora-devel-list at redhat.com>
> Date: 04/28/2009 10:36 AM
> 
>>
>> on my xfs root systems I still have hundreds of extents for this file.
>> Do you have xfs_fsr in a cron job?
>>
>> -Eric
>>
> 
> Here's a more accurate test. This is from another multi-year old system, 
> but this time xfs_fsr has never been run. It's currently on F9. 
> Originally F7 IIRC.
> 
> $ sudo filefrag /var/lib/rpm/Packages
> /var/lib/rpm/Packages: 325 extents found
> $ ll -h /var/lib/rpm/Packages
> -rw-r--r-- 1 rpm rpm 37M 2009-04-13 00:21 /var/lib/rpm/Packages
> $ df -h
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/mapper/VolGroup00-LogVol00
>                       297G   79G  219G  27% /
> 

The reason for this is quite obvious: RPM does first install the files of a 
package to disk and then update the rpmdb. This is repeated for each package 
to keep the rpmdb as close to the file system as possible. This means that 
the rpmdb grows for each package installed while there are other files 
written to disk in between.

Of course rebuilding the rpmdb fixes the fragmentation.

So, yes, rpmdb is a good candidate for further tweaking - possibly with pre 
allocation (nevertheless tweaking the db4 settings is prior on my list).

So another question: Is there a way to free no longer needed preallocated 
disk space again?

Florian