Elliptics and checksums
Current version supports data checksums calculated on every metadata write (happens after whole object is written to disk). By default we verify checksum for every READ and LOOKUP – this command returns link to requested object, which includes address of one of the hosting servers, file path on it, permission bits, object size and offset (if it lives within blob) and many other fields.
If checksum does not match error is returned. One can turn checksum verification off with per-request flag.
Check utilis do not yet support this feature, but we will teach them soon.
In a meantime we started to implement migration tool – this will be elliptics wrapper which will be able to move current group from its hosting machine to remote server. It will generate appropriate configs, copy all data and start new elliptics node instead of current one on another server. Very suitable for manual and automatic node migration from datacenter to datacenter.