Sidenote: Amount of Slots per Virtual Tape Library

Well, I just stumbled about this again (and I don’t know right now whether or not this is documented inside a RedBook or not) today, so I thought maybe I’m gonna write it down.

Slot-Amount Property of a Virtual Tape Library
Slot-Amount Property of a Virtual Tape Library

Please keep in mind, when creating the virtual library to think hard about the amount of slots you might need. It ain’t that bad, you just can’t decrease the amount anymore.  So if you think about creating 50 different virtual tape libraries with 500 slots each on your TS7530, think again. The current software level only supports 25.000 slots on a global level.

Working with IBM’s Virtualization Engine Console

Recently, we got the recommendation from our system partner to use static allocated tape cartridges instead of dynamic allocated ones. Apparently using dynamic allocating cartridges comes with a performance penalty if more than a few nodes are backing up a large amount of data at once.

And yet again, I noticed that the IBM Virtualization Engine Console (aka Falconstor Software) is really error prone.

In order to change the allocation type, we had to shred the old cartridges first (500 x ~100M up till now), chance the allocation type at the virtual tape library level, and then recreate the 500 cartridges with a fixed size (500x 102400MB). Now, as I was kinda optimistic, I decided to create all 500 cartridges at once.

Failure during the initiation of 500 virtual catridges

So I ended up creating the 500 cartridges in steps of 45. Which isn’t that big of a deal. But, as we do have two separate logical virtual tape libraries (basically the whole TS7530 is partitioned into two tape libraries), we had to do it for the second one too. But I told myself “Come on, try the maximum amount again!” … And guess what:

Successful initiation of 510 virtual catridges

That worked ❓ Please, don’t ask me why the hell it’s working for one virtual tape library on the same system (well, different virtualization engine), but ain’t for the other one … 😯