[stgt] how to setup a virtual tape using scsi-target-utils?

[Rob Evers]

On 07/16/2012 05:32 PM, ronnie sahlberg wrote:
> Can you verify that the tgtd target is running properly ?
>
>
> Just try to start it manually as root as :
>
> killall -9 tgtd
> tgtd
>
> and verify it is running by  netstat -tapn | grep 3260
>
>

Thanks, that worked.

I'm currently running into an issue where I try to configure
in over 256 virtual tapes via iscsi and on the initiator I see:

st 14:0:0:255: Attached scsi tape st254
st 14:0:0:255: st254: try direct i/o: yes (alignment 1 B)
st 14:0:0:255: Attached scsi generic sg256 type 1
scsi: host 14 channel 0 id 0 lun16640 has a LUN larger than allowed by
the host adapter
scsi: host 14 channel 0 id 0 lun16641 has a LUN larger than allowed by
the host adapter

Any idea why I would be seeing this?

The first 256 (0-255) tape devices look like they are configured
into the initiator correctly, and repeating this with the target
having 256 tapes appears to work.

Looks like  is due to the report_luns command not returning
the correct data from what I can tell on the host in
scsi_report_lun_scan:


                 result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
                                           lun_data, length, &sshdr,
                                           SCSI_TIMEOUT + 4 * HZ, 3, NULL);
.
.
.

         /*
          * Scan the luns in lun_data. The entry at offset 0 is really
          * the header, so start at 1 and go up to and including num_luns.
          */
         for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
                 lun = scsilun_to_int(lunp);
.
.
.

                 } else if (lun > sdev->host->max_lun) {
                         printk(KERN_WARNING "scsi: %s lun%d has a LUN 
larger"
                                " than allowed by the host adapter\n",
                                devname, lun);

I poked around a bit and found a fairly stale report of an identical 
problem:

http://old.nabble.com/-PATCH--Allow-more-than-255-LUNs-to-be-reported.-td19448136.html

>
> On Tue, Jul 17, 2012 at 5:25 AM, Rob Evers<revers at redhat.com>  wrote:
>> On 07/13/2012 07:08 PM, ronnie sahlberg wrote:
>>> Hi,
>>>
>>> If you just want to create a tape drive with a tape loaded, these
>>> commands should work :
>>>
>>> # create a blank tape
>>> tgtimg --op new --device-type tape --barcode 12345 --size 100 --type
>>> data --file /data/tape001.img
>>>
>>>
>>> # create a target
>>> tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.ronnie.test
>>>
>>> # create a SSC LUN for with the blank tape above loaded into the device
>>> tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 -b
>>> /data/tape001.img --device-type=tape
>>>
>> I get 'tgtadm: invalid request when trying to create the LU
>>
>> # tgtimg --op new --device-type tape --barcode 12345 --size 100 --type data
>> --file /data/tape001.img
>> blk_sz: 100, next 1152, 1152
>> Sizeof(mam): 1104, sizeof(h): 48
>> # tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.ronnie.test
>> tgtadm: can't send the request to the tgt daemon, Transport endpoint is not
>> connected
>>
>> At this, I did 'service tgtd restart'
>>
>> # tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.ronnie.test
>> # tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 -b
>> /data/tape001.img --device-type=tape
>> tgtadm: invalid request
>> #
>>
>> # tgtimg --help
>> Usage: tgtimg [OPTION]
>> Linux SCSI Target Framework Image File Utility, version 1.0.24
>>
>> [root at rhel-storage-03 ~]# tgtadm --help
>> Usage: tgtadm [OPTION]
>> Linux SCSI Target Framework Administration Utility, version 1.0.24
>>
>>
>> This is all after a fresh reboot.
>>
>> Am I still missing something?
>>
>> Rob
>>
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