rootninja

Make your own Virtual Tape Library with regular disk storage

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====

====$ sudo make install====

Now make the vtl user space daemons
====$ cd .. && make====

====$ cd /lib/modulesuname -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====


Posted on April 16th, by admica in Linux.
8 comments

8 thoughts on “Make your own Virtual Tape Library with regular disk storage”

  1. Hey
    you have to exec. “depmod -a”, to get the modul “working”! ;)

  2. I love it. Worked well in NetBackup but could not get the Medium Changer to work in TSM .. Any idea ?

    I get this in the SYSLOG:

    May 19 22:28:21 CentOS vtllibrary[17959]: SCSI s/n: (104)
    May 19 22:28:21 CentOS vtllibrary[17959]: 16 00 00 00 00 00
    May 19 22:28:21 CentOS vtllibrary[17959]: completeSCSICommand: op s/n: (104), sam_status: 0, sz: 5
    May 19 22:28:21 CentOS vtllibrary[17959]: SCSI s/n: (106)
    May 19 22:28:21 CentOS vtllibrary[17959]: 1a 08 1d 00 18 00
    May 19 22:28:21 CentOS vtllibrary[17959]: MODE SENSE **
    May 19 22:28:21 CentOS vtllibrary[17959]: Mode Sense 6 byte version
    May 19 22:28:21 CentOS vtllibrary[17959]: Page Control : Current configuration(0×0)
    May 19 22:28:21 CentOS vtllibrary[17959]: Page Code : 0x1d
    May 19 22:28:21 CentOS vtllibrary[17959]: Disable Block Descriptor => No
    May 19 22:28:21 CentOS vtllibrary[17959]: Allocation len: 24
    May 19 22:28:21 CentOS vtllibrary[17959]: find_pcode(0x1d): match pcode 29
    May 19 22:28:21 CentOS vtllibrary[17959]: completeSCSICommand: op s/n: (106), sam_status: 0, sz: 29
    May 19 22:28:21 CentOS vtllibrary[17959]: SCSI s/n: (107)
    May 19 22:28:21 CentOS vtllibrary[17959]: 1a 08 1d 00 18 00
    May 19 22:28:21 CentOS vtllibrary[17959]: MODE SENSE **
    May 19 22:28:21 CentOS vtllibrary[17959]: Mode Sense 6 byte version
    May 19 22:28:21 CentOS vtllibrary[17959]: Page Control : Current configuration(0×0)
    May 19 22:28:21 CentOS vtllibrary[17959]: Page Code : 0x1d
    May 19 22:28:21 CentOS vtllibrary[17959]: Disable Block Descriptor => No
    May 19 22:28:21 CentOS vtllibrary[17959]: Allocation len: 24
    May 19 22:28:21 CentOS vtllibrary[17959]: find_pcode(0x1d): match pcode 29
    May 19 22:28:21 CentOS vtllibrary[17959]: completeSCSICommand: op s/n: (107), sam_status: 0, sz: 29
    May 19 22:28:21 CentOS vtllibrary[17959]: SCSI s/n: (108)
    May 19 22:28:21 CentOS vtllibrary[17959]: b8 10 00 00 00 30 00 00 10 e0 00 00
    May 19 22:28:21 CentOS vtllibrary[17959]: READ ELEMENT STATUS **
    May 19 22:28:21 CentOS vtllibrary[17959]: Element type(0) => All Elements
    May 19 22:28:21 CentOS vtllibrary[17959]: Starting Element Address: 0
    May 19 22:28:21 CentOS vtllibrary[17959]: Number of Elements : 48
    May 19 22:28:21 CentOS vtllibrary[17959]: Allocation length : 4320
    May 19 22:28:21 CentOS vtllibrary[17959]: Device ID: No, voltag: Yes
    May 19 22:28:21 CentOS vtllibrary[17959]: completeSCSICommand: op s/n: (108), sam_status: 2, 0×05/0×24/0×00, sz: 5
    May 19 22:28:21 CentOS vtllibrary[17959]: SCSI s/n: (109)
    May 19 22:28:21 CentOS vtllibrary[17959]: 17 00 00 00 00 00
    May 19 22:28:21 CentOS vtllibrary[17959]: completeSCSICommand: op s/n: (109), sam_status: 0, sz: 5

    • I read in the docs that the author has tested it with NetBackup but has had problems in NetWorker. (docs are under /usr/share/doc/mhvtl*) The scsi command set is only partially implemented in the user space daemons. Perhaps you can make a patch to get it to work with other software and send it to the author?

    • I’ve used CommVault backup software. It’s my favorite enterprise level backup software. It has this capability and it works well.

  4. lovely peace of sw
    just set up my test virt machines with tsm and bacula
    and works like charm

  5. OK, I must have missed something. The writeup says, ‘first I downloaded mhvtl-2009-04-09.tgz . Fromwhere?

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