Improve the speed of some Tarsnap operations
Restore large archives faster
Tarsnap extract performance is currently latency-bound; the latency in question is client→EC2→S3, and the EC2→S3 step is about 50 ms.
The best workaround right now is to do parallel extracts; if you can split your data between multiple archives, or use --include and --exclude options when extracting so that each tarsnap -x is extracting a subset of the files, you should be able to use more bandwidth.
This process has been automated in at least one third-party tool.
Delete multiple archives faster
Multiple archives can be deleted with the same command; this is usually faster (and never slower) than using individual delete commands:
tarsnap -d \ -f mybackup-2015-08-07_13-52-46 \ -f mybackup-2015-08-09_19-37-20 \ -f mybackup-2015-08-14_08-22-34
In particular, deleting multiple archives at once allows tarsnap to cache metadata rather than downloading it multiple times. The speed-up therefore depends on how similar the archives are; if the archives are completely different then it will not save any time.