VXDUMP BACKUP

[Arun Jain]

Hi All,

I have a server with HP-UX B.11.23. A vxdump backup of the whole system is taken daily.
I don't know why it failed yesterday. Today also it is running very slow. It usually takes approximately 8 hrs and contains 16 file systems of approx. 937 GB. It uses 1 ULT-III tape.

Please suggest, what could be the problem
Regards :
Arun

[Jash_1]

Arun,

How is it being backed up? Over the network or via fibre, or SAN or it the tape drive scsi attached?

[Arun Jain]

Hi Jash,

backup is taken on LAN, means drive is attached with the server itself.

Regards :
Arun

[Bill Hassell]

> backup is taken on LAN, means drive is attached with the server itself.

I'm not clear about the backup. If the drive is attached to the computer, why is the LAN involved?

Just a note about LTO-3 tape drives and network backups (where the data is sent to another system). The LTO-3 requires a minimum of 60 MB/sec data flow with no compression, but really needs more than 100 MB/sec with compression turned on. This means that if you send all your data over a network, it will require a minimum of 2 and perhaps 4 1GB/sec LAN ports using APA software to keep up with the tape drive. A single LAN connection is much too slow for modern tape drives. The HP Ultrium-3 has the ability to slow down to as little as 20 MB/sec when the data is just too slow.

If the tape drive is connected directly to your system, you can expect 200 to 400 GB/hour (2-4 hours for your 937 GB of data). If the system is too busy during the backup period, the tape drive will slow down significantly.

As far as a failure, you should make sure vxdump documents the reason in a backup log. However, vxdump is a very poor choice for a backup program for more than a few GB of data. Like the archaic dump program, it tries to calculate the tape length and density, meaningless for hardware compression tape drives. It has no central index so checking a tape for a particular file will require one or more hours to read the entire tape.

To keep the LTO-3 busy, the backup program must stream several reader processes. The only built-in program is fbackup and properly configured for the LTO-3, should provide full backup speed. Additionally, fbackup has a central index and high speed restore capability (minutes rather than hours).

But with almost a terabyte of data, I would strongly recommend purchasing a real backup program such as Data Protector.