Backed up from DDS4 restore on DDS3.

[Worapoj P.]

Dear all expertise.

I got the problem with backup/restore about DDS3&DDS4 compatibility.
I would like to restore data from production machine to Testing machine that on Prod we backed up data with DDS-4 but on Testing machine it has just only DDS-3 drive.
HP Engineer sugest me to create device file for DDS-4 in format DDS-3 on Prod machine (actually physical drive is DDS4).
The problem is I've tried to use DDS device file to backup files with tar ,but every times it shown "tar: cannot open /dev/rmt/c5t0d0DDS3C"

Please helps
Thanks,
Worapoj

[Paula J Frazer-Campbell]

Hi

If you use a dds3 tape in the dds4 drive and the normal device file then all should be ok.


Paula

[U.SivaKumar_2]

hi,
what is the output of
#ioscan -fnC tape
what commands you used for creating the new
device file ?.

regards,
U.SivaKumar

[Worapoj P.]

Dear
Not OK ,because I backed up from DDS4 in DDS4 format but I have to restore on machine which have DDS3.
Workaround is create device file in format DDS3 on DD4 drive, but I couldn't backed up from this device file. The error is "tar: cannot open /dev/rmt/c5t0d0DDS3C"

Helps,
Worapoj

[Paula J Frazer-Campbell]

Hi

A DDS3 drive cannot read a DDS4 formated tape,

If you use a DDS3 tape in a DDS4 drive then the drive will use DDS3 format.

A DDS3 will read DDS1, DDS2 and DDS3 but not DDS4.


Paula

[Stefan Farrelly]

Theres a special option on mksf;

mksf -H -b DDS1 /dev/rmt/

You could have DDS1 or DDS2 so you can write these format tapes on say a DDS3 drive.

Once created do an lssf on /dev/rmt/ and it should say its down a DDS1 DAT.

You can substitute DDS1 for DDS2 or try DDS3. Do this on your DDS4 system, write to the new device file youve created, and on your DDS3 system you will be able to read the tape your wrote on your DDS4 server.

[Radhakrishnan Venkatara]

hi,

u cannot read a tape which is written on dds4 dat drive.
Problem lies below like this.
when u use a tape it uses compression tech of dds4 when use dds3 tape also it will writes using same compression method(this is for default device files ).
if u put dds4 tape in dds3 drive it will eject it automatically.
u can read dds3 written tape on dds4 but not dds4 written tape on dds3.

i don't how to create device files for dds3 support.


radhakrishnan