[hobbit] problem with disk test display

[Henrik Stoerner]

On Mon, Sep 19, 2005 at 06:46:23PM -0500, Craig Cook wrote:
> > On Mon, Sep 19, 2005 at 04:50:54PM -0400, Larry.Barber at usda.gov wrote:
> > > Henrik, it appears that having partitions removed from a Linux/Unix
> > > system messes up the disk drive display. The disk test continues to
> > > display the removed partitions (at least in the legend), but at the
> > > expense of not displaying all of the current partitions. In order to
> > > display all of the current partitions you have to manually remove
> > > the .rrd files that correspond to the removed partitions.
> > 
> > Ah yes - this is probably the same bug that Pat Vaughan reported
> > earlier today.
> 
> I would be wary about calling this a bug.  You should not be dropping file 
> systems without a good reason.  If you do drop a file system, you expect to 
> do extra work.  ie. locate rrd file and delete it (or run a command that 
> does it for you).

I understand your concern, but these things do happen occasionally.
Someone needs some temp. storage and mounts a normally unused partition.
Or a removable device (USB disks and memory sticks show up as SCSI
devices on Linux). Windows boxes report filesystems that come and go.

The solution i'm currently leaning towards would be to keep the number
of graphs what it is now (i.e. matching the number of disk mounts shown
in the latest "disk" status report), and then having the tool that
generates the graphs skip those RRD-files that haven't been updated
recently (within the past 24 hours). 

Combined with the new option I'm implementing that would allow you to
have a red disk status if some filesystem disappears from the disk
status reports, I think this would be a reasonable solution that doesn't
require me to do major changes to the way the jobs are currently divided 
among the hobbitsvc- and the hobbitgraph-CGI tools.

> I would be concerned if a tool automatically removed a disk parition graph 
> if it was not mounted at the time it was last checked.

Wouldn't it be OK to keep the RRD file - and the graph on the
"trends" column page - but remove it from the current "disk" status
display ?

> Maybe this should be made as a note in the documentation somewhere.

Absolutely.


Henrik