LVM and VxVM

Removing a SCSI DLT drive on line ???

 
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Mike Roger
Advisor

Removing a SCSI DLT drive on line ???


How safe, if it's ok to remove a SCSI DLT drive from a running HPUX system? The DLT is connected via a scsi cable to rp7400 system.

If it's safe what is the best way to do it? Is it switch off the DLT and remove the cable or just remove the cable. Will not this action hang up the bus or might blow fuses on controller?

Cheers,
Mike
14 REPLIES 14
T G Manikandan
Honored Contributor

Re: Removing a SCSI DLT drive on line ???

Do not do that.
Plan a downtime for the server for disconnecting the DLT from the server.

That device is not hot pluggable.The best way would be to bring down the server and then disconnect the drive.
Robert-Jan Goossens
Honored Contributor

Re: Removing a SCSI DLT drive on line ???

Mike,

If there is nothing else on the SCSI bus, power down the drive and remove it. This is NOT a recommended action by HP, but I've done it quit a few times. The worsed I've seen is a SCSI reset recorded by the OS.

Hope this helps,
Robert-Jan
Johan Lorimier
Frequent Advisor

Re: Removing a SCSI DLT drive on line ???

Hi,

trully HP will say it is not recommended, but if your drive is alone on the bus you can do it quietly. Power off the drive an then remove the cable. I have done it several times on HP9000 and alpha with just one incident (the internals drives were sharing the same SCSI bus with the DLT :-( ).

Johan
Mike Roger
Advisor

Re: Removing a SCSI DLT drive on line ???


Thanks for your time guys,

I'm getting two different answers so far, I need to hear more.

Donâ t do it : 1 TG
Do it quietly : 2 Johan & Robert

What dose HP says here? I need more details and what if the system was rp8400 and the cable is connected directly to the core I/O?

Later,
M
Naveej.K.A
Honored Contributor

Re: Removing a SCSI DLT drive on line ???

hi Mike,

Even though its not the recomended way to do so, I personally have done the same thing so many times. Switch off the DLT... and remove the scsi cable..

now in the case if you are connecting to the core i/o bus, there could be some other devices which are connected in the same bus and removing the device could result in a system hang becuase of scsi reset....this type of removal doesn't produce the same results always...but a bit risky if it is on the core I/O.

It could have the same impact on 8400 also...

with best wishes
Naveej
practice makes a man perfect!!!
Pete Randall
Outstanding Contributor

Re: Removing a SCSI DLT drive on line ???

Mike,

As long as you can be reasonably sure that there is no activity occuring on the SCSI channel, you should be able to remove the drive without any problem. I've got five of them on my backup server and swap failed ones in and out quite frequently.


Pete

Pete
harry d brown jr
Honored Contributor

Re: Removing a SCSI DLT drive on line ???

I've done this hundreds of times without a crash:

(1) power off drive
(2) get a terminator
(3) pull cable (on system)
(4) insert terminator (on system)

You have roughly 10 seconds before a SCSI timeout, so make it quick!

live free or die
harry
Live Free or Die
Mike Roger
Advisor

Re: Removing a SCSI DLT drive on line ???


Thanks again,

Harry, don't you think that the new LVD SCSI cards that comes with the rp systems are self terminated?

Cheers,
Mike
harry d brown jr
Honored Contributor

Re: Removing a SCSI DLT drive on line ???

Mike,

They are, but I usually terminate them anyway because I think it stops ioscans from searching the bus for devices that aren't there, but I could be wrong :-)

live free or die
harry
Live Free or Die