Martin Krischik $WikiTagline
 

A little DVDRam statistic for Linux

A DVDRam kann be formated under Linux with almost any filesystem you ever like. However there are differences in space and time.

The following statistics are the result of copying my internet download collection to three new DVDRams using the 3 diffrent formats

Speed

Time to copy
Formatrealusersys
vfat3251m28.367s0m0.664s0m15.566s
udf253m47.748s0m0.462s0m8.519s
xfs71m47.594s0m0.552s0m12.875s

real time is the time it took to copy - sys is the time where the CPU was actualy doing something - the difference the CPU was either waiting or doing something else. Sad that there is no DVDRam with SCSI - unlike IDE with SCSI the CPU is never waiting and could allways do something else.

The winner is of course udf2 with lowest sys time.

Please note

However this test is about writing to an new and empty dvdram. When replacing, adding and deleting files on an allready existing dvdram things looks different.

Especialy when reading and writing to a dvdram at the same time dvdrams become quite sluggish.

It's difficult to measure but I feel that xfs excels in this arena.

Size

Space occupied (human readable):
FormatDateisystemGrößeBenutVerfBen%Eingehängt auf
vfat32/dev/hdh4,3G1,9G2,4G44%/media/dvdram
udf2/dev/hdh4,3G1,9G2,5G44%/media/dvdram
xfs/dev/hdh4,3G1,9G2,4G44%/media/dvdram

As you can see the space differences are so minute that one has to look at the blocks to actualy see a difference:

Space occupied (2k blocks):
FormatDateisystem2K-BlöckeBenutztVerfügbarBen%Eingehängt auf
vfat32/dev/hdh2232020975784125623644%/media/dvdram
udf2/dev/hdh2236160974410126175044%/media/dvdram
xfs/dev/hdh2236192983115125307744%/media/dvdram

Now you can see that the winner is - again - udf with the most unused blocks.