Negative Hash Map error

Hi James

I have a small issue I can't seem to resolve. Every time I verify one of my archives I get the error "negative hash map does not agree with contrusted map". I follow the instructions and reindex the archive but the error persists upon re-verify. I have also tried repairing the archive.

Any ideas on why this is happening so much and what to do about it.

Thanks
Adrian

Adrian,

I suspect I might know what's going on. Please send a diagnostic report so I can look over the details.

Also, is the message you're getting a "failure" or just a "warning" or "caution?" Many negative hash map inconsistencies are not serious errors. Their only impact is a slight reduction in the efficiency in which QRecall can identify duplicate data blocks.

That's not to say the inconsistencies should happen; they shouldn't (thus the message). But the impact they have on your archive is truly inconsequential. So while I work on this issue, feel free to ignore it.

It's just a warning I think - a little blue exclamation mark rather than a slightly more scary triangular yellow exclamation mark.

I didn't think it was a serious issue but I thought it was worth just running it past you.

Adrian,

Your archive is fine. The reindex fixed the issue and it hasn't reoccured.

Looking through your logs, the "Negative hash map does not agree with contrusted map" message occurred once on 2013-01-01 00:02. At 2013-01-01 20:02 you reindexed the archive, and the capture and verify actions performed immediately after that show that the inconsistency was repaired (no message). The dozen or so actions that follow that all ran flawlessly, and didn't indicate any problems.

I've always suspected that this issue is due to a rounding error when dealing with deferred hash table entries. The consequences of having a negative hash map that is slightly out of sync with the hash table are so trivial, however, I've never dedicated a lot of time to tracking this down.

Should this issue reoccur, you can choose to ignore it or reindex the archive, whichever you're feeling like that day.

Adrian Chapman wrote:It's just a warning I think - a little blue exclamation mark rather than a slightly more scary triangular yellow exclamation mark.

Tip: Hover your cursor over the icon and a tool tip will explain the type/severity of the message.