Berry,
Do you have multiple channels going to the same control unit? You didn't
say. For example, does channel 10/11 go to one control unit and channel
12/13 go to another?
Also, you can make DDR ignore a volser depending on how you invoke it.
Regards,
Bill Stephens
Sr. Technology Analyst, High Availability
SunGard Availability Services
10th floor
401 North Broad Street
Philadelphia, PA 19108
Phone: (215) 351-1099
Fax: (215) 451-2045
[EMAIL PROTECTED]
Berry van
Sleeuwen
<berry.vansleeuwe To
[EMAIL PROTECTED]> [email protected]
Sent by: VM/ESA cc
and z/VM
Discussions Subject
<[EMAIL PROTECTED] DDR to DASD, on what paths
.UARK.EDU>
11/08/2005 11:10
AM
Please respond to
VM/ESA and z/VM
Discussions
<[EMAIL PROTECTED]
.UARK.EDU>
Hello list,
We have A VM that has DASD attached on 4 paths. The hardware is connected
on
ESCON Directors. Last week one of the cables was plugged into the wrong
director. Channels 10-12 were connected to director2, channel 13 was
connected to director 1. It is obvious that this will address a different
DASD.
Yesterday we used DDR to restore a tape to DASD.
<snip>
OUTPUT 3312 DASD SU3312
<snip>
When we started the copy DDR responded with: Volume Read : VM2076, etc. We
aborted the DDR and did a query of 3312, it responded SU3312. So we
suspected something wrong here and stopped to investigate. However, this
was
the second DDR restore. The first one should have been restored to 3311 but
in fact the data was placed on a different disk. The DDR did not report a
wrong dasd label. It looks like DDR queried the label, accepted the label
and started writing the data to DASD. But on a different channel and in
this
case on a different disk.
Now there is a discussion on how DDR and/or DASD IO will work in VM.
If an IO is executed in VM, is it always on the same channel?
Does DDR read the label and then write on the same channel?
Does DDR read the label before it writes a block of data or does it read
the
label only once?
Regards, Berry.
