[stgt] backingstore and tape configuration

[Mark Harvey]

On Thu, Oct 22, 2009 at 5:58 AM, Albert Pauw <albert.pauw at gmail.com> wrote:
> Just a simple question:
>
> How do I configure a tape drive target?
>
> Currently, the way I do it is like this:
>
> tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 -b
> /root/tapes/notape --device-type tape
> tgtadm --lld iscsi --mode logicalunit --op update --tid 1 --lun 1 --params
> vendor_id=HP,product_id="LTO3
> ULTRIUM",product_rev=0001,scsi_sn=012345678,scsi_id="HP LTO3
> ULTRIUM",removable=1
>
> I have to use a dummy tape (a tgtimg tape image with size 0) as I need a
> backingstore (I get an error otherwise),
> called in my case notape.
>
> Obviously, the mt command output shows that there is a tape in the drive:
>
> [root at orange ~]# mt -f /dev/nst0 status
> SCSI 2 tape drive:
> File number=0, block number=0, partition=0.
> Tape block size 0 bytes. Density code 0x0 (default).
> Soft error count since last status=0
> General status bits on (41010000):
>  BOT ONLINE IM_REP_EN
>
> Having ejected this dummy tape obviously gives the thing I want, an empty
> tape drive:
>
> [root at orange ~]# mt -f /dev/nst0 status
> SCSI 2 tape drive:
> File number=-1, block number=-1, partition=0.
> Tape block size 0 bytes. Density code 0x0 (default).
> Soft error count since last status=0
> General status bits on (50000):
>  DR_OPEN IM_REP_EN
>
>
> So, is there a way to define an empty tape drive without using a dummy tape?

There doesn't seem to be a way at the moment.

This functionality change a few months ago (while I wasn't monitoring
this list very much)..

Perhaps a default change to not having to mount a backing store via
"--op new", and the mounting of a backing store to be performed later
via an "--op update" - For all devices - even for non-removable
devices ?

This is an issue for all removable type targets (MMC, SSC).
Specifying a backing store for SMC does not make sense - although the
backing store for SMC could be used for storing the Medium Auxiliary
Memory (MAM)

My 2c worth.
Mark

>
> Thanks,
>
> Albert
>
>
>
>
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