Tape Drive SCSI pass-through


New Member
Apr 3, 2012
Hello i need to get a Tape Device LTO-3 working.

I try SCSI pass-through as described here http://pve.proxmox.com/wiki/Tape_Drives.

But i get allways the Error Message "kvm: -drive file=/dev/sg4,if=none,id=drive-scsi4,aio=native,cache=none: could not open disk image /dev/sg4: Invalid argument"!

Is it not possible to pass-through the Tape device??

I was trying to use Proxmox (Performance ist great) against ESXi, but with no
SCSI pass-through this is useless.

Please help me to stay with Proxmox!!


try cache=writethrough instead of cache=none.
try cache=writethrough instead of cache=none.

Hello i have tried, but now i have this Error message:

"kvm: -device scsi-block,bus=scsihw0.0,scsi-id=4,drive=drive-scsi4,id=scsi4: scsi-block: INQUIRY failed
kvm: -device scsi-block,bus=scsihw0.0,scsi-id=4,drive=drive-scsi4,id=scsi4: Device 'scsi-block' could not be initialized"

not really. I recommend you use a backup software supporting remote tape device agent, this is the only reliable way (AFAIK).
have you checked that the tape is really /dev/sg4? or permission issues?
does the tape device work with any cli tool on proxmox host as /dev/sg4?

For anyone who cares about this, I eventually had to run up a host with centos 5.6, a version of ietd that supported rawio patch (iscsitarget-0.4.17) . Something like this on a fresh minimal centos 5.6 machine;yum install gcc kernel-devel kernel-headers openssl-devel lsscsidownload iscsitarget-0.4.17, extractrun this patch in kernel dir (you'll need to download it)patch -p1 < iscsitarget-0.4.17.rawio.patchmakemake installvim /etc/iet/ietd.confTarget iqn.2013-09.localdomain.localhost:tape Lun 0 H=2,C=0,I=5,L=0,Type=rawio (use settings from lsscsi) Type 1 InitialR2T No ImmediateData Yes xMaxRecvDataSegmentLength 262144add to modules on bootecho modprobe iscsi_trgt >> /etc/rc.moduleschmod +x /etc/rc.modulesput in /etc/rc.d/rc.local;nohup /usr/sbin/ietd -c /etc/iet/ietd.conf -d 2 -f &As for some reason it would only pick up the device properly if running on console... whatever, it works now.
I just test with tgt - seem to have better support for passthrough - will post results later.


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