Sounds like your SAN is needs some love.
From: Gary Baluha [mailto:user-ae3e15c22de1@xymon.invalid]
Sent: Thursday, November 29, 2007 3:26 PM
To: user-ae9b8668bcde@xymon.invalid
Subject: Re: [hobbit] strange graph behavior - random machines &
graphs
Some additional information... If I delete the RRD files that
become corrupted like this and let them rebuild, not only does it
rebuild it corrupted again, but if you click on the graph for the full
history, all four of the historical graphs show the exact same corrupted
data. That is, it has a full 576 days worth of corrupted, invalid data,
even though the RRD file has only had data going to it for a handful of
Hobbit polling cycles.