Benchmarks version 3.1

Filesystem with fragment size 512.

Filesystem under test was an AIX 4.1 filesystem with fragment size of 512 bytes. The filesystem had 35940 files covering 1212844 KB of data. As a comparison, this filesystem has been defragmented under different circumstances. First table shows how long it takes for the defragmentation to run before the filesystem is defragmented. Changing parameters are version of utility and available free space in the filesystem.
 
free space Version 2.2.0 Version 3.1.0
65108 KB real    2h47m27.94s
user    3m34.32s
sys     1h12m58.78s		 real    2h14m39.91s
user    4m2.99s
sys     25m19.61s
128556 KB real    2h11m21.23s
user    1m40.62s
sys     31m22.83s		 real    2h1m57.81s
user    2m16.05s
sys     21m56.21s
1392640 KB real    1h58m6.63s
user    1m58.59s
sys     21m26.56s
The following table shows the performance numbers after the defragmentation of the backup benchmark to /dev/null.
 
Elapsed time Performance 
Improvement
Before 
defragmentation		 real    15m42.78s
user    0m45.20s
sys     2m7.30s
Version 2.2.0 
defragmentation		 real    10m57.00s
user    0m43.91s
sys     2m5.19s		 30%
Version 3.1.0 
defragmentation		 real    7m45.67s
user    0m43.59s
sys     2m5.87s		 50%

Performance improvement for version 2.2.0 went from 942 seconds to 657 seconds or an improvement of 30%.

Performance improvement for version 3.1.0 went from 942 seconds to 465 seconds or an improvement 50%.

Big file enable filesystem.

Testing was conducted on a big file enabled filesystem. Filesystem size was only 1.2 GB. This is insufficient for creating files larger then 2 GB (unless they have many holes) but is sufficient to demonstrate the impact of the file layout. Files larger then 4 MB are handled differently then files smaller then 4 MB.

Filesystem was created by performing a backup/restore : this way is the best you can create a filesystem with minimal fragmentation and only using standard AIX tools.

Fragmentation was first check by executing place on the filesystem : 

# ./place -v--f /dev/home3
#
# file locator (C) Compunix v3.1.0 for AIX 4.3. For more info : ./place -h
#
Vol: /dev/home3 (4096 byte blocks). AIX V4.2 filesystem type.
Fragment size 4096. Compression not activated, big file enabled
File accessed since 1 days, 00:00:00 are emphasis.
Scanning 20 filesystem aggregates....................
Number of used inodes = 35908
Fragments 39713 (best case 35493, worst case 294795)
Space efficiency :
Math. average = 99.08394%, Geo. average = 98.09551%
Space sequentially :
Math. average = 99.29664%, Geo. average = 99.26469%
Overall filesystem seq.  87.6695% (fragments = 35493 --> 100%, fragments = 294795 --> 0%)
Running the benchmark before defragmentation : 
# time (find . -print | backup -iqf /dev/null)
real    8m13.68s
user    0m42.64s
sys     1m54.76s
After running defragmentation, fragmentation was checked again by executing place on the filesystem : 
# ./place -v -f /dev/home3
#
# file locator (C) Compunix v3.1.0 for AIX 4.3. For more info : ./place -h
#
Vol: /dev/home3 (4096 byte blocks). AIX V4.2 filesystem type.
Fragment size 4096. Compression not activated, big file enabled
File accessed since 1 days, 00:00:00 are emphasis.
Scanning 20 filesystem aggregates....................
Number of used inodes = 35908
Fragments 35507 (best case 35493, worst case 294795)
Space efficiency :
Math. average = 99.97236%, Geo. average = 99.91556%
Space sequentially :
Math. average = 99.99917%, Geo. average = 99.99913%
Overall filesystem seq.  99.6082% (fragments = 35493 --> 100%, fragments = 294795 --> 0%)
All numbers have improved. The real test is however the benchmark test which generated following result : 
# time (find . -print | backup -iqf /dev/null)

real    6m50.86s
user    0m44.82s
sys     1m52.42s
From 493 seconds elapsed time to 410 seconds or an improvement of 20%

Benchmarks version 2.1

Filesystem under test was an AIX 4.1 filesystem with fragment size of 512 bytes. The filesystem had 14000 files covering 473212 KB of data.

Execution time before defragmentation :

Execution time after defragmentation : Total elapsed time went from 431 seconds to 359 seconds resulting in 20% faster access.

Another benchmark was executed on a AIX 4.3 system, defragmentation an AIX 4.1 filesystem with fragment size of 512 bytes, The filesystem had 25000 files covering 900 MB of data.

Execution time before defragmentation :

Execution time after defragmentation : This is shows an improvement of 26.9% real time.
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