Mozy says that the bugs reported by users concerning repeated full backups were not bugs at all, instead reflecting a feature of the product.
An EMC spokesperson said: "Basically, we concluded that there was no bug. We just didn't explain clearly to our customers how Mozy works with external drives. We've reached out to everyone on that thread that you referenced."
He said Mozy was not a backup service for external drives: "In the interest of clarification, we want to be clear about something upfront: Mozy is a backup service for fixed drives, not an archival solution, so external hard drives create something of a special case."
"If an external hard drive is disconnected from a user’s computer for any reason, our servers assume that they are candidates for deletion in 30 days (which is how long Mozy stores files that have been removed from a customer’s fixed drives).
"When the external drive is later reconnected, it appears to be backing up when in fact it is only reassigning the backup set on the customer’s machine. This information can be found in our Knowledge Base article number 77277."
EMC said this information has been posted to the thread referenced in our story, as it is the root cause of each customer’s issue.
Forum community administrator Mike Jones included this paragraph in his posting on the fifth page of the thread: "We are continuously working to improve our service and minimise the occurrence of these scenarios [when an external drive is unplugged]. Our latest release, 2.2, has several improvements included in it that should greatly help.
"Future versions will more intelligently detect what files on external drives are new and what is already backed up. This will reduce the frequency of the checking process."
He added that files may be re-uploaded if it has been patched, or is a small file or when a clean version is needed for data integrity reasons. Also a file re-upload may occur if: "the servers can't find the file in a timely manner - After a certain amount of time, if the servers haven't located the file, it will assume the file doesn't exist and ask for the file to be re-uploaded even if the file already exists."
"We are currently rolling out an optimisation plan to free up some of the workload from the servers (most notably the optimisation work done at the latter part of last week which may be why it is working a lot better now). With the servers working more efficiently, re-association will work much better."
That's alright, then... ®