Guests with SCSI Pass Through Tape Drives don't start or crash

[jessor]

We have a problem with SCSI Pass Through as documented on pve.proxmox.com/wiki/Tape_Drives.

Guests with scsi0 configured (Windows and Linux) don't start on boot, shutdown hard seconds till minutes after start.

Tried .24, .32 and current .35 kernel. The tape drive is a Tandberg Quikstor RDX (300GB) running on a SATA bus.

Suspicious messages in syslog:

kvm[3075]: segfault at 0 ip (null) sp 0000000040afaea8 error 14 in kvm[400000+28a000]
kvm: 3403: cpu0 unhandled wrmsr: 0x198 data 0
kvm[3411]: segfault at 0 ip (null) sp 00000000429e9ea8 error 14 in kvm[400000+28a000]

System:

# cat /sys/class/scsi_generic/sg?/device/model
CDDVDW TS-H653J
RDX
RAID 5/6 SAS 6G

# grep scsi /etc/qemu-server/102.conf
scsi0: /dev/sg1

# pveversion -v
pve-manager: 1.7-11 (pve-manager/1.7/5470)
running kernel: 2.6.35-1-pve
proxmox-ve-2.6.32: 1.7-30
pve-kernel-2.6.32-4-pve: 2.6.32-30
pve-kernel-2.6.35-1-pve: 2.6.35-9
pve-kernel-2.6.24-12-pve: 2.6.24-25
qemu-server: 1.1-28
pve-firmware: 1.0-10
libpve-storage-perl: 1.0-16
vncterm: 0.9-2
vzctl: 3.0.24-1pve4
vzdump: 1.2-10
vzprocps: 2.0.11-1dso2
vzquota: 3.0.11-1
pve-qemu-kvm: 0.13.0-3
ksm-control-daemon: 1.0-4

 

[tom]

try with the 1.8 packages (just use pvetest repo in your sources.list and update) - 1.8 will be released soon, probably tomorrow. better?

scisi will not work in windows (no stable scsi drivers available in newer windows), try with Linux.

 

[jessor]

Thanks. Didn't work, though.

Mar 29 13:53:59 proxmox qm[3048]: VM 102 start failed: command '/usr/bin/kvm -monitor unix:/var/run/qemu-server/102.mon,server,nowait -vnc unix:/var/run/qemu-server/102.vnc,password -pidfile /var/run/qemu-server/102.pid -daemonize -usbdevice tablet -name Intranet -smp sockets=1,cores=1 -nodefaults -boot menu=on -vga cirrus -tdf -k de -drive file=/var/lib/vz/images/102/vm-102-disk-1.raw,if=ide,index=0,cache=none,boot=on -drive file=/dev/cdrom,if=ide,index=2,media=cdrom -drive file=/dev/sg1,if=scsi,index=0,cache=none -m 512 -netdev type=tap,id=vlan0d0,ifname=tap102i0d0,script=/var/lib/qemu-server/bridge-vlan -device e1000,mac=DA:5F:95:55:E06,netdev=vlan0d0' failed with exit code

# pveversion -v
pve-manager: 1.8-15 (pve-manager/1.8/5754)
running kernel: 2.6.35-1-pve
proxmox-ve-2.6.32: 1.8-32
pve-kernel-2.6.32-4-pve: 2.6.32-32
pve-kernel-2.6.35-1-pve: 2.6.35-10
pve-kernel-2.6.24-12-pve: 2.6.24-25
qemu-server: 1.1-30
pve-firmware: 1.0-11
libpve-storage-perl: 1.0-16
vncterm: 0.9-2
vzctl: 3.0.24-1pve4
vzdump: 1.2-11
vzprocps: 2.0.11-1dso2
vzquota: 3.0.11-1
pve-qemu-kvm: 0.14.0-2
ksm-control-daemon: 1.0-5

 

[tom]

edit the VMID config file and add cache=writethrough.

scsi0: /dev/sg1,cache=writethrough

 

[jessor]

With writethrough, the Debian/Lenny guest hangs right after

Booting the kernel.
pci 0000:00:01.0: PIIX3: Enabling Passive Release
Loading, please wait...

The windows 2003 guest crashes like before.

 

[tom]

what about using a remote tape agent? e.g. if you live in the windows world the Backup Exec Linux Tape Media agent is known to work well.

 

[jessor]

Tom, I'm usually not living in the windows world (thankfully). But no offense taken ;-)

I'll look into Backup Exec. Thanks for your support.

 

[tom]

Tom, I'm usually not living in the windows world (thankfully). But no offense taken ;-)

I'll look into Backup Exec. Thanks for your support.

using remote tapes will also work with linux tools, just depends on your backup software. this way enables migration of the backup VM/container, therefore its more practicable than doing a pass through.