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backup dds3

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Robert Pieters
Occasional Advisor

backup dds3

Every night we make a full backup of our UX-server on a dds3 tapedrive. It's about 13 GB and it takes 11 hours.
Is this normal ??? If not, what can we do to increase this time ?

Greetings Robert
Chris Wilshaw
Honored Contributor

Re: backup dds3

What software are you using to perform the backup?

If it's fbackup, you can specify a config file to use

eg fbackup -vf -c .........

The config file can contain a number of options (see fbackup man page), but one of the most useful is

blocksperrecord 128

(the default for this value is 16)

Adding this in (if not already present) should speed up your backup
Donald Kok
Respected Contributor

Re: backup dds3

Hi Robert,

DDS3 does 1 Mb/sec =3,6 Gb/hr. So your speed is not OK.

You should check all the components in the path (from disk to tape) and check the speed of it to find the bottleneck.

You could provide the forum more info (f.i. which backup program; what system; backup over network)

Good luck
My systems are 100% Murphy Compliant. Guaranteed!!!
Leif Halvarsson_2
Honored Contributor

Re: backup dds3


The DDS3 drive can reach a performance of 3.6GB/h native and 7.2GB/h compressed , the drive is not the bottleneck.
What kind of data do you back up and which backup program do you use. Can you describe your enviroment.

Michael Tully
Honored Contributor

Re: backup dds3

If our not backing up to a local tape drive then this is a big problem, bad tapes, or more likely bad drive. From these stats, you must be running your backup over a network, in which case backups times will depend on how much traffic is being experienced over your network.
Anyone for a Mutiny ?
Stefan Farrelly
Honored Contributor

Re: backup dds3

There are some fbackup config options which can really make your backup run much faster. These are the optimum values we use in our /var/adm/fbackupfiles/config file (see man fbackup);

blocksperrecord 128
records 32
checkpointfreq 256
readerprocesses 4
maxretries 1
retrylimit 0
maxvoluses 1000

The other major factor is the DDS3 drive being on a SCSI bus of its own - ie. not sharing with any disks. This can slow it down a lot if its sharing a bus.
Im from Palmerston North, New Zealand, but somehow ended up in London...
T G Manikandan
Honored Contributor

Re: backup dds3

The admins are talking about fbackup.
Through my experience if you are using tar,then it takes quite some time to backup the amount of data.
11 hours is ok.


Ulf Lipski

Re: backup dds3


there are two points of discussion. The first is how is the backup down by the hard- and software, the second is what data
is ist.

First use for the backup device a separate scsi-path. Check if compression is enabled at the tape device and check if your are using the approbiate devive /dev/rmt/... . If possible use a fw-scsi-tape, e.g. dlt7000. A common mistake is to connect a dlt-tape with single ended scsi!

Look at your data choosen for backup. Normally it takes more time if you get a bunch of small files to backup and it takes less time for a few big files.
Last give some info about the server, the model. If it is slow then think about another backup plan.

By, Ulf
Optimization is the root of all evil.