Knowledgebase: Volume handling
Interpret error counters
Posted by Sven Koester, Last modified by Sven Koester on 14 April 2009 7:27
The volume information page contains a section Error Counters where non-recoverable and recoverable volume errors over the volume lifetime are accumulated.|
Non-recoverable write and read errors
These errors indicate usually a defect medium and cause PresSTORE to flag the medium as suspect. The medium can still be reused, but mostly, the volume will report non-recoverable errors again.
Keep in mind that there may be other reasons causing the supect flag to be set. E.g., in case an unexpected volume is found in the "wrong" slot of a jukebox, it may as well be flagged as suspect, even if no access errors occurred.
Recoverable write and read errors
Recoverable errors are shown as re-writes and re-reads in the user interface.
PresSTORE does not interpret these counters on it's own, the values are shown as informative items. These errors indicate that either the medium itself is old or worn out, or that the drive is dirty and needs cleaning.
There are ways to gather experience about the drive's behaviour. Unfortunately, each drive has its own characteristics, depending on the technology. Sometimes, 100's of recovered errors are quite normal, sometimes they indicate the tape is nearly worn out. Because of that, there are no general absolute numbers that can be used to rate the usability of a volume.
It is recommended to: