Your private tape library – a pre-configured virtual machine with MHVTL and iSCSI export capability

I am using MHVTL for quite a while now. MHVTL emulates a configurable tape library and stores the data in the file system. Normally when testing i am installing the backup software directly where MHVTL runs. But that only works for simple configurations.

For complex configurations for instance with drive sharing this approach does not work. A few days ago i sumbled accross the idea to export the tape library and the drives via iSCSI. So i made a VM based on Oracle Enterprise Linux 6 Update 2 plus the most recent MHVTL version plus self-compiled tgt to test this. And in fact: It does work without any major problems.

With this blog post i would like to share my VM with all interested people. You can download the VM here (728 MB). The root password is ‘root’.

VM Details

The VM itself is based on Oracle Enterprise Linux 6 Update 2 and pre-configured with MHVTL (a tape emulation software) and tgt (an iSCSI implementation). MHVTL is pre-configured as a library with 39 slots and 4 LTO-5 drives (cartridge capacity of 500 MB).

TGT is also pre-configured to export the library and tapes via iSCSI. The configuration is in /etc/tgt/targets.conf. Everything starts up automatically. After starting the VM you have to configure the network youself!

Altough this VM was developed with VMWARE you can use it under Virtual Box as well. Everything should be compatible. The hardware is configured to  2 CPU Cores, 2 GB RAM and consists of two virtual disks: One disk “sda” with 20 G used in a LVM for volume group ‘vgroot’ and a second disk “sdb” with 100 GB used in a LVM for volume group ‘vgvtl’.
Volume Groups ‘vgroot’ and ‘vgvtl’ are intended to separate the operating system from the VTL tape data. The file system mounted on /opt/mhvtl is a BTRFS for maximum flexibility. Note that BTRFS is still marked as ‘experimental’.

The VM should be compatible with any kind of backup software supporting tape libraries. I can confirm it works with EMC Networker.

Using the library over iSCSI

To present the tape library and its drive to a client using iSCSI just do on the client:

iscsiadm --mode discovery --type sendtargets --portal <VTL VM IP>
iscsiadm --mode node --targetname <FROM ABOVE> --portal <VTL VM IP> --login

After that you should see the tape drives and the changes with ‘lsscsi -g’. If EMC Networker is installed you can also use the ‘inquire’ tool:

[root@mhvtl-client ~]# inquire
scsidev@0.0.0:NECVMWarVMware IDE CDR101.00|CD-ROM, /dev/sg0
scsidev@1.0.0:VMware, VMware Virtual S1.0 |Disk, /dev/sg1
scsidev@1.1.0:VMware, VMware Virtual S1.0 |Disk, /dev/sg2
scsidev@2.0.0:IET     Controller          |(Unknown Device Type c), /dev/sg3
                                           S/N:                               beaf10
                                           ATNN=IET     00010000
scsidev@2.0.1:IBM     ULT3580-TD5     0102|Tape, /dev/nst0
                                           S/N: XYZZY_A2
                                           ATNN=IBM     ULT3580-TD5     XYZZY_A2
                                           WWNN=50223344AB000200
scsidev@2.0.2:IBM     ULT3580-TD5     0102|Tape, /dev/nst1
                                           S/N: XYZZY_A1
                                           ATNN=IBM     ULT3580-TD5     XYZZY_A1
                                           WWNN=50223344AB000100
scsidev@2.0.3:IBM     ULT3580-TD5     0102|Tape, /dev/nst2
                                           S/N: XYZZY_A3
                                           ATNN=IBM     ULT3580-TD5     XYZZY_A3
                                           WWNN=50223344AB000300
scsidev@2.0.4:IBM     ULT3580-TD5     0102|Tape, /dev/nst3
                                           S/N: XYZZY_A4
                                           ATNN=IBM     ULT3580-TD5     XYZZY_A4
                                           WWNN=50223344AB000400
scsidev@2.0.5:STK     L700            0102|Autochanger (Jukebox), /dev/sg8
                                           S/N: XYZZY_A
                                           ATNN=STK     L700            XYZZY_A
                                           WWNN=50223344AB000000

If that was successfull you can for instance configure the tape library:

[root@mhvtl-client ~]# jbconfig

Jbconfig is running on host localhost (Linux 2.6.32-300.3.1.el6uek.x86_64),
  and is using mhvtl-client as the NetWorker server.

         1) Configure an AlphaStor Library.
         2) Configure an Autodetected SCSI Jukebox.
         3) Configure an Autodetected NDMP SCSI Jukebox.
         4) Configure an SJI Jukebox.
         5) Configure an STL Silo.

What kind of Jukebox are you configuring? [1] 2
14484:jbconfig: Scanning SCSI buses; this may take a while ...
Installing 'Standard SCSI Jukebox' jukebox - scsidev@2.0.5.

What name do you want to assign to this jukebox device? JUKEBOX
15814:jbconfig: Attempting to detect serial numbers on the jukebox and drives ...

15815:jbconfig: Will try to use SCSI information returned by jukebox to configure drives.

Turn NetWorker auto-cleaning on (yes / no) [yes]? no

The following drive(s) can be auto-configured in this jukebox:
 1> LTO Ultrium-5 @ 2.0.2 ==> /dev/nst1
 2> LTO Ultrium-5 @ 2.0.1 ==> /dev/nst0
 3> LTO Ultrium-5 @ 2.0.3 ==> /dev/nst2
 4> LTO Ultrium-5 @ 2.0.4 ==> /dev/nst3
These are all the drives that this jukebox has reported.

To change the drive model(s) or configure them as shared or NDMP drives,
 you need to bypass auto-configure. Bypass auto-configure? (yes / no) [no]

Jukebox has been added successfully

The following configuration options have been set:

> Jukebox description to the control port and model.
> Autochanger control port to the port at which we found it.
> Autocleaning off.
> Barcode reading to on.
> Volume labels that match the barcodes.

You can review and change the characteristics of the autochanger and its
        associated devices using the NetWorker Management Console.

Would you like to configure another jukebox? (yes/no) [no]

Conclusion

I hope you like this VM and it makes you life a little bit easier. If you have any comments or problems feel free to leave a comment or drop me a mail.