Why are files that are being modified during backup missing or corrupted?
There are 3 types of files that change as Cloud Backup backs them up:
- Files that are being overwritten or get deleted as we back them up.
- Files like logs that get appended to as we back them up.
- Files like databases that may have random updates to any part of them as we back them up.
If files are modified during backup, they may be:
- Overwritten or Deleted: These files are not guaranteed to have usable content or to even be included in the backup at all.
- Appended: We will make a best effort to back these up, but we expect to be able to restore a reasonable and usable form of these files.
- Randomly Updated: We do not in any way guarantee that these files will be restorable, and even if they are restored, we do not guarantee that what is restored is not corrupt.
These file types either change too rapidly (databases, logs, caches) or don't exist long enough to be backed up (session files). Session files should be avoided entirely. And if the information is valuable to your business, log files should track it. Caches should also be avoided, as their data is meant to be discarded.
If you do need to back up these files, our suggested workarounds are:
- For databases—Take a snapshot of the database (e.g., a database dump) and back up the dump. See Rackspace Cloud Backup - Backing up Databases for full instructions.
- For log files—Take snapshots of your log files and back them up.
- To avoid running out of disk space, rotate your log files periodically.
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