I was wondering if anyone has experimented with targeting Amazon S3 as a SyncTarget?
It wouldn't be rsync of course - it would need to use Amazon's protocol - but presumably you could set RsyncOptions to something that would work with an S3 sync script and put a wrapper around rsync to catch options that require that the S3 script is used instead of rsync.
http://www.s3rsync.com/index.php/Rsync_to_Amazon_S3 looks like a promising drop-in, if the metered costs are OK.
Reported on Movable Type 4.2
Hmm... I notice that s3rsync stores .tar files in the S3 bucket, which makes sense to preserve bandwidth for using S3 for backups, so it doesn't look like a good fit, unles I'm missing a trick.
Further thoughts...
Looks to me like all that's needed is RsyncPath to point to a simple file copy script, which handles the PUT to S3.
http://www.movabletype.org/documentation/appendices/config-directives/rsyncpath.html
Bearing in mind that the file will have been modified, it will always want to be copied across, so there's no real need for rsync cleverness at all?!
I worry that the file transfer will consume some time and I wonder if this isn't going to be heavy for run-periodic-tasks. I guess the time taken for rsync is the precedent. If it is comparable, it should be OK.
To get really clever for this it would be good to be able to differentiate content that is unlikely to be updated and give it a custom header with expires set for the far future, where applicable for reasons explained at http://developer.yahoo.com/performance/rules.html#expires. I guess images could get the far future header, but otherwise it would be good to be able to differentiate "permalink" content with no comments and make that far future and handle content that we want to update with some regularity and depend on ETag and HTTP/304 for those. The content could be grepped for something that flags that... I wonder what?