dd if=something you want to read from something
dd of=something means you want to write onto something
if you omit if, stdin will be used instead
if you omit of, stdout will be used instead
see man dd

ok i tried several tapes all give me the same error about space
i do rewind them first
then this

read: Not enough space
0+0 records in
0+0 records out

did you write anything on those tapes?
does it work really locally?
probably you have a disk full somewhere...

all tapes have data - verified from log files
i can not test locally due to limited hd space , thats why i am doing this via ssh to extract data on another computer's disk which has a lot of free space
640G 175G 433G 29% /orastage

for example , i have this tape inserted in the tape drive now

there is data , this is the log file

tar cvf - *20161006* | ssh root@192.168.1.2 dd of=/dev/rmt/1
obs=126b

421289640+0 records in
3343568+1 records out

real 609m23.025s
user 102m56.737s
sys 11m12.550s


i try to dd if , i get the same errors like before

ssh root@agrotica dd if=/dev/rmt/1 obs=126b | tar xvf -
Password:
read: Not enough space
0+0 records in
0+0 records out
tar: This does not look like a tar archive
tar: Error exit delayed from previous errors


the path where i am telling it to extract the file has 433gb free space

probably there is no space (enough) on the remote host (agrotica) somewhere

agrotica is where the tape drive is mounted to . Does it matter if that machine has limited space left ? I Why should it matter though ? i just want to copy data off the tape via ssh to another host

Your dd command is trying to read the tape at the wrong block size. Instead of "obs=126b" use "bs=126b".

1 members found this post helpful.

oh yes, forgotten to say. i means input, o means output, so dd if= ibs= and dd of= obs= belong together.

1 members found this post helpful.

ok i will try ssh root@192.168.1.2 dd if=/dev/rmt/1 bs=126b | tar xvf - in a few and i will report back

bs=126b did the trick , seems to be working ok so far

thanks