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backup very slow

siva baskaran
Regular Advisor

backup very slow


we using tape array 5300 in rp4440 server actually we had to take backup only 250gb size but it taking very long time like 9 hrs for to be completed 30 or 40 %, and we are using vxdump command file system is vxfs and drive speed is 80 gb/hrs.
command is

vxdump -0uf /tapepath /filesystem
so please anybody give me solution for taking back up as much as fast

Ivan Ferreira
Honored Contributor

Re: backup very slow

The backup time can very depending of the content of the file system, if your file system contains a lot of very small files, backup will be very slow, if you have a few large files, backup will be faster.

You can test your device speed by using:

dd if=/dev/zero of=/tapepath bs=8192 count=131072

This will save to tape 1 GB. You can use iostat to check the throughput.

You can also use LT&T to test the device.

Finally, ensure that you are not getting errors on the system log.
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
Satish M.S.
Valued Contributor

Re: backup very slow


What are you running for an OS? Is it OpenVMS?. Also I know this sounds trivial, sincee the drives are hot swap, try to reseat the drive and see if this is of any help whatsoever. And ofcourse, depending on your OS you can download Library and Tape Tools Diagnostic from

Also could you pleas elaborate on the nature of the data/information that is being backed.



Re: backup very slow

You cld use drive and system performance tests available in L&TT, to identify the source of the problem
Honored Contributor

Re: backup very slow


1. What kind of tape drive are you using?
2. Is it reallyrated at 80 GB/hour? And is this "compressed"?
3. What kind of filesystem are you backing up? Fewer large files or millions of smaller files?

Depending on your tape drive's capability - you may want to try using a blocking factor to your vxdump command like so:

vxdump 0ubf 512 /dev/rmt/1mn /filesystem

You may also want to play around with media density and size arguments to vxdump. See "man vxdump"

Hakuna Matata.