Comment 2 for bug 457082

In order to prevent to harm the boot process, the defragmentation could stop after a delay (30 seconds ?).

The big files shouldn't be defragmented since it has low probability to be a library or a program.

For the file size trigger, I think 14 MB is a good tradeoff since it may catch all 32bit libraries:
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j@j-lt:~$ find /usr/lib -type f -size +14M -iname "*.so*"
j@j-lt:~$ find /usr/lib -type f -size +13M -iname "*.so*"
/usr/lib/libicudata.so.40.1
j@j-lt:~$
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