Ssync

Ssync, an optimised S3 sync tool using the power of Unix!

• Ruby 1.8 or 1.9
• RubyGems
• 'aws-s3' and 'thor' rubygems
• find, xargs and openssl

gem install ssync

To configure, run ssync setup and follow the prompts, you'll need your AWS keys, the local file path you want to back up, the bucket name to back up to, and any extra options to pass into find (i.e. for ignoring filepaths etc). It'll write the config to ~/.ssync/my-s3-bucket.yml.

To sync, run ssync sync and away it goes.

In the case of a corrupted/incomplete synchronisation, run ssync sync -f or ssync sync --force to force a checksum comparison.

If you would like to sync to more than one S3 buckets, you may do so by:

ssync setup -b my-s3-bucket
ssync sync -b my-s3-bucket

ssync setup -b another-s3-bucket
ssync sync -b another-s3-bucket

Running ssync setup and ssync sync without any bucket names defaults to using the last bucket you used.

Use the command below to get to the help screen.

ssync help

This library was written because we needed to be able to back up loads of data without having to worry about if we had enough disk space on the remote. That's where S3 is nice.

We tried s3sync but it blew our server load (we do in excess of 500,000 requests a day (page views, not including hits for images and what not, and the server needs to stay responsive). The secret sauce is using the Unix find, xargs and openssl commands to generate md5 checksums for comparison. Seems to work quite well for us (we have almost 90,000 files to compare).

Initially the plan was to use find with -ctime but S3 isn't particularly nice about returning a full list of objects in a bucket (default is 1000, and I want all 90,000, and it ignores me when I ask for 1,000,000 objects). Manifest generation on a server under load is fast enough and low enough on resources so we're sticking with that in the interim.

FYI when you run sync, the output will look something like this:

[Thu Apr 01 11:50:25 +1100 2010] Starting, performing pre-sync checks ...
[Thu Apr 01 11:50:26 +1100 2010] Generating local manifest ...
[Thu Apr 01 11:50:26 +1100 2010] Fetching remote manifest ...
[Thu Apr 01 11:50:27 +1100 2010] Performing checksum comparison ...
[Thu Apr 01 11:50:27 +1100 2010] Pushing /tmp/backups/deep/four ...
[Thu Apr 01 11:50:28 +1100 2010] Pushing /tmp/backups/three ...
[Thu Apr 01 11:50:29 +1100 2010] Pushing /tmp/backups/two ...
[Thu Apr 01 11:50:30 +1100 2010] Pushing local manifest up to remote ...
[Thu Apr 01 11:50:31 +1100 2010] Sync complete!

You could pipe sync into a log file, which might be nice.

Have fun!

• Ryan Allen
• Fred Wu

This project is brought to you by Envato Pty Ltd.