Hi, After messing around for a while trying to optimize the ncbi downloads, I realized independent of the rsync costs that simply FTPing the formatted files was the best bet. Even that was a bit tricky since the files might change while you're downloading them. I no longer have to deal with this problem, but what I wished at the time was that some brave soul, perhaps bio-mirror, would offer a bit torrent of, say, Monday's snapshot of a file. Then every subsequent day, a bit torrent would be offered of the diffs of the unpacked file vs. the previous unpacked version. Sites that wished to keep up with daily changes could apply the patches, while less critical applications could just get the weekly distribution. Running a bit torrent client would require server resources, but the actual load on your servers should be reduced significantly. -steve