Reduce utility
Just imagine that
- you have installed new software on your AIX system and cleanup the temporary installation files. The result is an /usr-filesystem with MBs of free space which you can't reclaim for another filesystem. The disk-spaced wasted is more then 100MB !!!.
- you have given the wrong parameter for increasing the size of a filesystem. Instead of increase by 10000 blocks, you've typed 100000 blocks. Result : a filesystem which is 90000 blocks to big !!!
Your alternatives for recovering are :
- in case you have additional disks available, create a new filesystem (with the new preferred size), copy all your files, remove the old filesystem and rename the new filesystem.
- when no disks available, you could also use tapes for doing backup/restore
- previous method will not work for /usr, that would require re-installing your system.
All of the described methods involve either additional disks, plenty of time and/or a complete system re-installation.
The reduce capabilities of this package allows you to reduce any journalled filesystem in AIX. The current version works on unmounted filesystem, but it is possible to reduce also the root-filesystem and /usr-filesystem. In the latter case you need to work in maintenance mode (either boot from diskette, tape or CD-ROM).
Starting with version 3.1, reduce operation can be prepared online and as such reducing the time that the filesystem must be unmounted.
With version 4.1, support was introduced fro AIX 5.1 and the enhanced journalled filesystem or JFS2.
Support Matrix
| AIX 4.x | AIX 5.1 | AIX 5.2 | AIX 5.3 | |
| JFS | supported | supported | supported | supported |
| JFS2 | N/A | supported | supported | N/A |
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