[mrtg] please help with detail graph issue Resolved

[Steve Shipway]

> The problem has been resolved. The issue seems to be with the rrdtool
> version 1.3.1. We rolled back to version rrdtool-1.2.27 and everything
> works.

Aha - this may be related to the 'lazy mode' bug, which was in 1.3.0 (affecting routers2) but I believed it to have been fixed in v1.3.1.

Basically, to be more efficient, routers2 (and probably mrtg-rrd) enable 'lazy mode' when asking to create the graph images.  If the existing image age is sufficiently young that it does not need to be recreated then RRDtool will not bother to waste time recreating it - the bug was causing RRDtool to then output incorrect graph sizes.  In this case, we may have something similar, or the graph is not being created, or is created corrupt.

There is a patch for routers2 that will disable lazy mode completely to get around this (v2.19 actually detects RRD 1.3.0 and disables lazy mode itself) so if you still want to try it out then let me know.  I may make this a permanent option in the routers2.conf as well in v2.19.

It is worth trying out this workaround because, if it is a lazy-mode bug, then Tobi needs to be notified so that he can investigate.

Steve