RE: Critical disk usage amount

["Andy Nolen-Parkhouse" <aparkhouse@xxxxxxxxx>]

Dave,

A few thoughts:

- You won't commonly get performance issues in your range, but if your
disk capacity ('utilization' is often reserved for activity) has the
capacity to grow rapidly, then you need a large buffer.

- I seem to remember a rule of thumb:
70% - Plan for disk
80% - Order disk
90% - Install disk

- The results of reaching 100% are rather severe, particularly if no one
notices those pesky little messages.  If a request for test data is
likely to push you well above 90%, then you need a larger buffer.

- If you know your disk configuration, perhaps you can make a good
argument with management for more storage.  If additional storage can be
had for just the cost of a drive, then you may have an easy argument.  If
you need a new controller and RAID set, then it's more difficult.  If you
need an expansion chassis, an HSL cable, a controller, and a RAID set,
then it may be impossible until something really bad happens.

- Track the time spent managing disk space after automating what you can.
If you're spending a lot of time move stuff around, backing it up and
then deleting it, make sure that folks know that there is a cost
involved.

- Track the growth of production data so that you can anticipate when you
must buy more disk.

- If you disk activity (on the WRKDSKSTS display) is at 40% or above,
then you have an argument for installing additional disk, whether you
need the capacity or not.

All in all, 74% is a decent place to be.  I wouldn't panic.

Regards,
Andy Nolen-Parkhouse

> On Behalf Of Dave Snyder
> Subject: Critical disk usage amount
> 
> I am trying to convince people here that we need to add more disk to
> our AS400. We currently have 256GIG and are at 74% utilization. What
> common usage percentage do people use as a threshold that, if we go
> beyond this percentage, there will be issues?
> We have cleared off as much as possible but people constantly want more
> test information left on the box, so we continue to grow every month.
> Thanks for the thoughts.
> Dave