dd and cpio

[Juan M Leon]

Hello everyone, I am looking for some help with combining dd and cpio.


I found the following info usng the bellow command, however my brain is not working and I dont see how to use the same commands to list and restore the files....

Anyone have suggestions for me thanks

find /dir1 /dir2 /dir3 /dir4 /dir5 -depth | cpio -ov 2> /daily_files/`date -u +%d%b%y`.data | dd of=/dev/rmt/2m obs=1024k

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=856576&admit=-682735245+1190358717477+28353475

[AwadheshPandey]

use
dd if=/daily_files/`date -u +%d%b%y`.data of=/dev/rmt/2m obs=1024k

[Juan M Leon]

Pandei,

Thank you for your prompt response, but I think I already placing the data to the tape in my command, what I want to do is read from the tape...

Thank you

[Dennis Handly]

I assume you just reverse things, to list:
dd if=/dev/rmt/2m ibs=1024k | cpio -ivt

To restore:
dd if=/dev/rmt/2m ibs=1024k | cpio -idm

I assume obs= and -B are not required since you are sending it through the pipe.

[Dennis Handly]

You probably can increase the performance by adjusting the block size to match the pipe:
obs=5120 | cpio -idmB

[Pete Randall]

Forgive the OT (off-topic) reply.

I'm trying to get the #Replies counter for this thread to increment itself.


Pete

[Juan M Leon]

Denys,
Thank you for your reply, I will test your suggestions.

[Juan M Leon]

Dennys,

I tried the commands you suggested. I will think it should work however i got the following error:

# dd if=/dev/st0 obs=1024k | cpio -ivt
dd: reading `/dev/st0': Cannot allocate memory
0+0 records in
0+0 records out
0 bytes (0 B) copied, 3.02205 seconds, 0.0 kB/s
cpio: premature end of archive


Any ideas...
Thanks in advance

[Dennis Handly]

>Pete: I'm trying to get the #Replies counter for this thread to increment itself.

I had problems with this thread too. It would disappear and then it would still have 0 replies. ??

>I tried the commands you suggested. ... i got the following error:
# dd if=/dev/st0 obs=1024k | cpio -ivt
dd: reading `/dev/st0': Cannot allocate memory

I had ibs=1024k.

Also it appears you are using some foreign devil dd(1) because HP-UX's version doesn't print "Cannot allocate memory" or "0 bytes (0 B) copied, ...".

[Peter Nikitka · Accepted solution]

Hi,

the name of the device file '/dev/st0' sounds to me like you work on Solaris.
Is there a remsh/ssh connection in play?

If all is local, it should not be necessary to use dd at all; your command should be identical to
find /dir1 /dir2 /dir3 /dir4 /dir5 -depth | cpio -ov 2> /daily_files/`date -u +%d%b%y`.data >/dev/rmt/2m

mfG Peter

[Dennis Handly]

>Peter: sounds to me like you work on Solaris.

That would be pretty foreign. :-)

>If all is local, it should not be necessary to use dd at all;

Won't that have a trivially small block size, that's why they had tcio? At least -B should be used.

[Peter Nikitka]

Hi,

Dennis' remark should be included, Juan.
Give that a try:
find /dir1 /dir2 /dir3 /dir4 /dir5 | cpio -oBv 2> /daily_files/`date -u +%d%b%y`.data >/dev/st0

For verification, nothing has to be changed:
cpio -ivt
mfG Peter

[Dennis Handly]

>Peter: For verification, nothing has to be changed: cpio -ivt
Shouldn't that have a -B too? -iBvt

[Juan M Leon]

Thanks all for your response.
First of all you were right, this is not HPUX. My apologies I thoug that dd and cpio will be the same in any platform.
I guess I was wrong the linux cpio is a GNU.
That explains the error reported.

At the end I used tar for some reason I was able to save the data (140GB) onto tape using cpio however I was unable to restore the data.

Thanks all for your advise.