Due to eventual consistency nature of elliptics there may exist a window in which replicas are not in sync.

Depending on various factors this window may be rather large, for example in our production clusters we run this kind of check weekly, so having replica outdated for that long may require additional steps to get synchronized data.
We store metadata for every written object, which among others contain update timestamp. So it is quite simple task to make a parallel request for metadata from multiple replicas in different datacenters and select the one with the latest timestamp.

This exists in elliptics API quite for a while, and now I added it to pohmelfs.
At open() time we check all replicas and build a list of groups, where it is present, sorted by timestamp, so any subsequent read will get the must up-to-date data.

As a bonus I added keepalive mount options to detect broken links early. In our tests where datacenters may shutdown on weekly basis waiting for couple of hours is a bit of overhead to detect it.

There are 2 pohmelfs tasks to date - http compatibility mode, where object ID is generated according to its full path, and umount bug, which is likely because of my dirty dcache games.