Reality of delta benefit

In case this is useful to the delta storage debate...

The other day, in the process of figuring out how big a farm to buy, I ran a
size analysis on the EROS source repository. Basically, I expanded every
version ever and examined the disk consumption in blocks under various
compression schemes: RCS, gzip, bzip2, etc.

Somewhat to my surprise, RCS is only very slightly better than gzip (normal
compression -- nothing fancy) on this data set and roughly the same as
bzip2.

Is this comparable to other measurements people have seen? If so, it strikes
me that storing deltas in the repository itself may multiply I/O's and file
operations for very little benefit.

shap
Received on Sat Oct 21 14:36:07 2006