cp from one drive to antother. mb/sec?

hondaman · 10-15-2005, 03:48 PM

If im doing a large file copy from one drive to another on the same box, how can i measure, easily, what my mb/sec throughput is?

ioerror · 10-15-2005, 04:07 PM

The quick, ad-hoc way is to time the copy 'time cp ...' and divide that into the file size.

I don't know of any util that can directly measure the mb/sec from a copy (as there are buffering/cacheing issues to take into consideration).

However, running (as root) 'hdparm -t /dev/hdX' will give you an approximate measure of your drive's thoughput. 'hdparm -T /dev/hdX' will read from cache, thus testing your memory/processor throughput. See the hdparm man page for more details.

hondaman · 10-15-2005, 04:18 PM

Yeah, i was aware of the time thing, but i was hoping for a more elegant way of doing it.

Hammett · 10-15-2005, 04:23 PM

You can use gkrellm, that can monitor activity on your HDDs with the transfer rate.

hondaman · 10-15-2005, 05:06 PM

Ah, thats a start, but now i might be asking for too much by seeing if there was a command line version of something that will measure transfer speed for a particular file copy?

debianmike · 10-15-2005, 05:14 PM

wont hdparm -tT tell you your transfer rates?

ioerror · 10-15-2005, 05:18 PM

Quote:

wont hdparm -tT tell you your transfer rates?

Did I not mention this already. Why is everyone ignoring me?

Hammett · 10-15-2005, 05:21 PM

AFAIK there's no command line that will take account on file transfer rates, only monitoring tools like gkrellm are able to do so.

hondaman · 10-15-2005, 05:22 PM

Id like to measure a particular instance of a file copy, or simultaneous file copies. If I understand you correctly, hdparm is something i run once, and it gives me a baseline number, but doesnt tell me exactly how fast an individual file copy is going.

ioerror · 10-15-2005, 05:26 PM

No can do. Linux uses extensive buffering and drive cacheing. There's no way that I know of to turn it off to see the raw I/O speed on a drive.

debianmike · 10-15-2005, 05:37 PM

Quote:

Did I not mention this already. Why is everyone ignoring me?

did anyone else hear something?