1st, apologies if this has been asked before. I remember I faced this issue few years ago, but do not remember exactly what my calculations were.
Basically, I have a medium size database (over 100GB) that needs a reindex job for 1st time. I know for sure, it will hit space hard that 1st time, but I do have some space constraints so I may run out of space before the job completes.
How can I calculate the amount of space required for the Tlog so the job won't fail? I am currently calculating that with top 5 tables and adding a 10 to 20 percentage to that. Is that correct? I know the best way to know this is after the job runs, but that's not an option here. So I am looking for a ballpark number based on some math and educated guess.
Any other comment or suggestion is welcome.