[Info-vax] Replacement of SCSI tape drives and loaders

[Syltrem]

"FrankS" <sapienza at noesys.com> a écrit dans le message de news: 
108fbd62-f1e2-40f4-b994-6489ac129c3f at d14g2000vbb.googlegroups.com...
On Jan 21, 2:11 pm, "Syltrem" <syltremz... at videotron.ca> wrote:
> Hi
>
> I have 2 Alpha servers, each with SCSI connected tape drive(s)
>
> I want to move the drives from one server to another, and install a new 
> one.
>
> QUESTION: Can I do this live ?
>
> My experience (on VAX) is that I can disconnect / reconnect the same drive
> on the VAX and it will not notice, as long as I DO NOT attempt to use the
> drive (do a MOUNT or INIT etc) on it while it is disconnected. Doing so
> would crash the VAX.
>
> On Alpha it may be different, the HP tech says it should work just fine. I
> just want to double check here.
>
> Details :
> On the AS4100 I have a standalone DLT4 drive MKB600
> On the ES40 I have a TL891 mini-library with 2 DLT4 drives MKA400 and 
> MKA500
>
> I want to disconnect the standalone DLT4 drive from the AS4100 and connect
> the TL891 and its drives in replacement.
> On the ES40 in replacement of the TL891 I want to install a new LTO4 
> drive.
>
> So... the AS4100 will get 2 drives instead of 1, and the ES40 will loose 
> one
> drive and the replacement one will be of a different model.
>
> QUESTIONS:
> - Should I care about the new drives SCSI addresses ?
> - VMS on the ES40 will continue to see the old device (let's say MKA500 if
> the new one replaces MKA400) which is disconnected. If by mistake some
> process tries to access it, will it cause VMS to crash ?
> - If I keep the same SCSI address, does it matter if suddenly (as far as 
> VMS
> sees it) the drive model is different ?
> - The speed of the drive is also different. Without a reboot will VMS make
> the best use of the new unit (the speed of the devices on the bus have
> changed) ?
>
> This is NOT something I've done before so I just don't know.
> My guess is that I should shutdown the servers to do this, but I'd rather
> not if it's not required (24/365 shop)
>
> Merci
> Syltrem

> a) I would double check that the interface is the same across all the
> drives.  That is, are they all using LVD or HVD SCSI?
>
> I suspect the TL891 is HVD, and the LTO will be LVD.  This may
> sidetrack your plans.
>
> b) I'm in the habit of using the following:
>
> $ MC SYSMAN
> SYSMAN> IO SCSI
> SYSMAN> IO AUTO
>


Thanks for the hint on
SYSMAN> IO SCSI

I will do this as well. I'm writing my scenario right now.

I will do my disaster recovery server first before I try that in production 
!
Thanks to all who provided guidance on this config change !
Syltrem