What makes some 'pacct' records be written out of order (i.e. late)

NickVarley_Metron

I work for a software company that amongst many other things captures data from the 'pacct' file for Linux (and other UN*X environments). I would have though that as process accounting data is written when a command ends that all data in the 'pacct' file would be in strict date/time order of completion.

Oh, that it were so easy.

I've seen many examples of Linux data out of order, by various times - maybe a few minutes "late", maybe 8 hours "late", i.e. later than the other data around it. There's never a lot of it, and I can't find any rhyme or reason to what appears to get delayed, and I've checked the content of various 'pacct' files to confirm that the data really is in there out of order, and I'm not somehow reading it badly.

Can anyone shed any light on this?

What could make the write of 'pacct' file data occasionally not get done until some time in the future?

Any ideas or pointers most welcome!