Tuesday, January 10, 2012

Solaris and tape drives

I was faced with an interesting question today: we have a DDS tape drive of some sort attached to a Solaris machine, and a tape we need to read from. How do we discover what type of tape drive it is, what device it's attached with, and go get some data off the tape?

To show attached SCSI devices: cfgadm -al lists a tape device at rmt/3

To show the device details: iostat -E

bash-3.00# iostat -E
st4       Soft Errors: 0 Hard Errors: 0 Transport Errors: 0
Vendor: ARCHIVE  Product: Python 04687-XXX Revision: 6610 Serial No:þÊݺþÊݺþÊݺ

Looked up the Python 04687-XXX - it's a DDS-2 tape drive according to

The tape we wanted to restore from is a DDS-1 (identified by looking here):
A tar tf /dev/rmt/3 failed - I guess the DDS-2 drive expects to find a DDS-2 tape in there, not a DDS-1. Maybe it would be happier if we told it to use a low-density type of tape?

You can tell the tape drive what density to use depending on which device
file you refer to - details here:

To get Solaris to read from it as a low-density device: mt -f /dec/rmt/3l status

or tar xvf /dev/rmt/3l
And it works! 

1 comment:

  1. For the record, this also works for Solaris 8 and a similar tape device, the Python 04687-XXX6580. I did have to boot -r to make Solaris see the tape drive, though.