moving a DLT8000 without restarting the L class server

[Padraig Stafford]

Hi all,

I've got an external Quantum DLT 8000 drive with a Fast Wide Differential card attached to
a HP9000 L2000 server which I would like to move to a HP9000 D280 server for 1 day of testing.

The L class is our production box so I would rather not have to restart it to do this, does
anybody know if it is ok to move this DLT drive with the boxes up and running ?

Any ideas gratefully received.

[Vincent Fleming]

Removing a SCSI device from a running system is not recommended, unless you are setup to do so... meaning, unless it's a hot-pluggable device.

The reason for this is that the SCSI bus will, at least for a moment, be unterminated. This can cause problems.

In a more practical sense, you can remove a device if you are really, really, really sure that the SCSI bus it's attached to is not being used and will not be used during the time which it's unterminated.

Most admins shy away from doing such things on production machines... particularly if they've been around a while - in the "old days" it was possible (probable, actually) that you would damage either the device or interface card by hot-plugging it. I haven't seen a machine get damaged like that in years, though.

So, in summary, it's not supported, it's not a good idea, but if you really really really need to do it, it can probably be done without damaging anything - if you're really really really careful.

Did I mention that it's not supported? (sorry - I have to wear my employee hat once in a while)

Good luck!

[harry d brown jr]

I agree with Vince, although I have done it, it's dangerous.

You also have an issue with the DEVICE FILE, if it's not already in your production systems kernel, then you need to add it and reboot your production box.

live free or die
harry

[Jon Mattatall]

The above are correct. I'll just throw in the experimental evidence.

We've done it here. At this point, we're running at about a 20 to 1 success rate.

The keys are to be sure the bus is inactive, power the drive off, and remove the connector ALL AT ONCE. Do not "wiggle" it off (that applies to attaching it as well). Think of it as being like removing a Band-Aid. Wiggling can create potentials across pins, and BOOM.

The thing is, when it goes bad it goes completely bad and the I/O card is toasted. That's what happened in the "1" case I mentioned (not me, thankfully). You have to decide if the risk is worth it or not.

Jon