dd command to test disk

[lawrenzo_1]

Hello,

How do you tell of there is a problem with a disk by running:

# dd if=/dev/rdsk/c4t13d0 of=/dev/null bs=512k

I have been told this will tell you if there is a problem so what output would you expect?

TY

[saju_2 · Accepted solution]

Hi

Check this thread

http://forums2.itrc.hp.com/service/forums/questionanswer.do?threadId=237706&admit=-1335382922+1121295007871+28353475

If the disk has problem it will give i/o error

Regards
CS

[Mel Burslan]

either it will complete successfully by saying something like

xyz+w bytes in
xyz+w bytes out

which means it could successfully be read from all across the platters.

if there are some bad blocks, the program will abort abnormally giving some sort of an error message that I can not recall now. It has been ages since I have not seen one.

[Joseph Loo]

hi,

as the others have mentioned, the records in and records out must be the same and complete successfully.

u do not have to wait for the output to be shown, by "breaking it" (ctrl+c), the output of the dd command will also be shown.

regards.

[lawrenzo_1]

thanks I wasn't sure as I ran the commnad and had to do ctrl+ D to gre the output.

[Patrick Wallek]

I know you already closed this, but I had to chime in.

I would recommend using a block size larger that 512k. That is awfully small and will take a while to complete. I would go with 4096k or 8192k. The test should still accomplish the same thing, but be a bit faster.