Gaurenteed file write??

[Greg Freemyer <freemyer@xxxxxxxxxxxxxxxxx>]

All,

I have an iteration counter that I update every night.

    echo $ITERATION > /backup/iteration

Recently this file was reset to 0.

I suspect it was a case of the "zero filled file".

For this specific file and shell script, what extra logic can I add that would 
give me the highest likelihood of a successful disk write.

i.e. Would sync; sync;  increase my odds of always successfully writing this 
file out?

TIA
Greg Freemyer