rootninja

I know there’s already big companies making Virtual Tape Library (VTL) devices, but they’re expensive and I’m just looking for a cheap solution for testing. And it’s working quite well so far as a proof-of-concept for my needs.

After setting it up you should see a media changer and a basic set of tape drives using by using dmesg or lsscsi.

$ sudo dmesg | grep scsi

sr0: scsi3-mmc drive: 1x/1x xa/form2 cdda tray
sr 2:0:0:0: Attached scsi CD-ROM sr0
sd 0:0:0:0: Attached scsi generic sg0 type 0
sr 2:0:0:0: Attached scsi generic sg1 type 5
scsi3 : mhvtl: version 0.15.11 [20090328-0], opts=0×0
scsi 3:0:0:0: Medium Changer STK L700 5400 PQ: 0 ANSI: 5
scsi 3:0:0:0: Attached scsi generic sg2 type 8
scsi4 : mhvtl: version 0.15.11 [20090328-0], opts=0×0
scsi 4:0:0:0: Sequential-Access QUANTUM SDLT600 5400 PQ: 0 ANSI: 5
scsi 4:0:0:1: Sequential-Access QUANTUM SDLT600 5400 PQ: 0 ANSI: 5
scsi 4:0:0:2: Sequential-Access QUANTUM SDLT600 5400 PQ: 0 ANSI: 5
scsi 4:0:0:3: Sequential-Access IBM ULT3580-TD4 5400 PQ: 0 ANSI: 5
scsi 4:0:0:4: Sequential-Access IBM ULT3580-TD4 5400 PQ: 0 ANSI: 5
scsi 4:0:0:5: Sequential-Access IBM ULT3580-TD4 5400 PQ: 0 ANSI: 5
scsi 4:0:0:6: Sequential-Access SONY SDX-900V 5400 PQ: 0 ANSI: 5
scsi 4:0:0:7: Sequential-Access SONY SDX-900V 5400 PQ: 0 ANSI: 5
scsi 4:0:0:0: Attached scsi generic sg3 type 1
scsi 4:0:0:1: Attached scsi generic sg4 type 1
scsi 4:0:0:2: Attached scsi generic sg5 type 1
scsi 4:0:0:3: Attached scsi generic sg6 type 1
scsi 4:0:0:4: Attached scsi generic sg7 type 1
scsi 4:0:0:5: Attached scsi generic sg8 type 1
scsi 4:0:0:6: Attached scsi generic sg9 type 1
scsi 4:0:0:7: Attached scsi generic sg10 type 1
st 4:0:0:0: Attached scsi tape st0
st 4:0:0:1: Attached scsi tape st1
st 4:0:0:2: Attached scsi tape st2
st 4:0:0:3: Attached scsi tape st3
st 4:0:0:4: Attached scsi tape st4
st 4:0:0:5: Attached scsi tape st5
st 4:0:0:6: Attached scsi tape st6
st 4:0:0:7: Attached scsi tape st7

This host is a VMware 32-bit Fedora 10 installation running on VMware Server 2.0. I’ll try it on a real piece of hardware with a dedicated disk mounted where the tape data gets written to.

Start by getting the source here. I grabbed the mhvtl-2009-04-09.tgz file containing the userspace and kernel module source code.

Make the kernel module first.

$ tar xvzf mhvtl-2009-04-09.tgz

$ cd mhvtl/kernel && make

make -C /lib/modules/2.6.30-rc2/build SUBDIRS=/home/test/mhvtl-0.15/kernel modules
make[1]: Entering directory `/usr/src/kernels/2.6.30-rc2-i686'
  CC [M]  /home/test/mhvtl-0.15/kernel/mhvtl.o
  LD [M]  /home/test/mhvtl-0.15/kernel/vtl.o
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /home/test/mhvtl-0.15/kernel/vtl.mod.o
  LD [M]  /home/test/mhvtl-0.15/kernel/vtl.ko
make[1]: Leaving directory `/usr/src/kernels/2.6.30-rc2-i686'

$ sudo make install

install -o root -g bin -m 755 vtl.ko /lib/modules/`uname -r`/kernel/drivers/scsi/

Now make the vtl user space daemons

$ cd .. && make

make -C usr
make[1]: Entering directory `/mhvtl-0.15/usr'
make[1]: Nothing to be done for `all'.
make[1]: Leaving directory `/mhvtl-0.15/usr'

$ cd /lib/modules`uname -r`/kernel/drivers/scsi

This might be because i’m doing this in a VMware virtual machine, but modprobe would not see the vtl.ko at all, yet insmod would load it. The scripts use modprobe, so I manually loaded it with insmod to get around this problem for now.

$ sudo insmod vtl.ko

Launch the init script.

$ sudo /etc/init.d/vtl start