How to generate a tape device.

How to generate a tape device.

1.install and setup the scsi target
# rpm -q scsi-target-utils || yum -y install scsi-target-utils (perl-Config-General)
2.disable iptables and selinux.
# service iptables stop
# chkconfig iptables off
# setenforce 0
3.setup the tape target.
# service tgtd start
# tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.st:tape:sttarget1
# tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL
# dd if=/dev/zero of=/root/tape.device bs=1M count=100
# tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --device-type tape --lun 1 -b /root/tape.device
# tgtadm --lld iscsi --op show --mode target
Target 1: iqn.st:tape:sttarget1
    System information:
        Driver: iscsi
        State: ready
    I_T nexus information:
    LUN information:
        LUN: 0
            Type: controller
            SCSI ID: IET     00010000
            SCSI SN: beaf10
            Size: 0 MB, Block size: 1
            Online: Yes
            Removable media: No
            Prevent removal: No
            Readonly: No
            Backing store type: null
            Backing store path: None
            Backing store flags:
        LUN: 1
            Type: tape
            SCSI ID: IET     00010001
            SCSI SN: beaf11
            Size: 1049 MB, Block size: 1
            Online: Yes
            Removable media: Yes
            Prevent removal: No
            Readonly: No
            Backing store type: ssc
            Backing store path: /root/tape.device
            Backing store flags:
    Account information:
    ACL information:
        ALL
4.install and setup the iscsi initiator
# rpm -q iscsi-initiator-utils ||  yum -y install iscsi-initiator-utils
# iscsiadm -m discovery -t st -p 127.0.0.1
Starting iscsid:                                           [  OK  ]
127.0.0.1:3260,1 iqn.st:tape:sttarget1
# iscsiadm -m node -l
Logging in to [iface: default, target: iqn.st:tape:sttarget1, portal: 127.0.0.1,3260] (multiple)
Login to [iface: default, target: iqn.st:tape:sttarget1, portal: 127.0.0.1,3260] successful.
# rpm -q lsscsi || yum install -y lsscsi
# lsscsi | grep -w tape
[11:0:0:1]   tape    IET      VIRTUAL-TAPE     0001  /dev/st0

5.launch a KVM guest with this tape device passthrough to guest(note: cache=none not support for scsi-generic).
e.g:...-drive file=/dev/sg3,if=none,id=drive-data-disk,format=raw -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x7 -device scsi-generic,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-data-disk,id=data-disk

6.login to guest to check the tape device work well.
# lsscsi | grep -w tape
# tar cvf /dev/st0 /root/sluo