bs option on dd copy command

[Joel Shank]

I need to copy a large number of raw logical volumes from one device to another and plan on using dd. Does anyone know how the bs parameter effects the copy? How large can it be and what effect will a large value vs a small value have on the time it will take to copy the data? I know that the blksize must be a multiple of the device blksize and am assuming that this is the blksize on the filesystem (VxFS) that has been created on the device. Is that a correct assumption?

Thanks in advance for your assistance,
jls

[Robert-Jan Goossens_1 · Accepted solution]

Joe,

Here is a discussion about dd and the block size.

http://forums1.itrc.hp.com/service/forums/parseCurl.do?CURL=%2Fcm%2FQuestionAnswer%2F1%2C%2C0x464d5c7609e9d61190050090279cd0f9%2C00.html&admit=-682735245+1134485057349+28353475

Regards,
Robert-Jan

[Joel Shank]

Thank you, Robert-Jan
That was exactly what I was looking for.

Can you tell me how you searched to get that answer? I tried searching 4 or 5 times and never got close to a answer that pertained to my question.

Thanks again,
jls

[James R. Ferguson]

Hi Joel:

Use Google and limit your search domain to 'itrc.hp.com'.

Regards!

...JRF...

[Sยภเl Kย๓คг]

Hi,
Search in itrc itself, with dd command as search string.

regards,
Sunil

[Joel Shank]

Mischief managed.