Throttling down copy speed (using the cp or rsync commands)

[dreamspy]

Hi

I'm wondering if it's possible to throttle down the transfer speed when copying files with cp or rsync?

The reason I ask is that I have to do a massive 2TB copy between two arrays on the same computer, taking about 17 hours. When I start the copy all network users get terrible transfer rate. This copy is not that important and I don't mind throttling the speed down a bit. The transfer speed to my network users is more important.

There might even be another solution, maybe giving network traffic higher priority?

I tried using the "nice -n 19 cp source target" command but it didn't have any effect, probably because nice is aimed at setting priority for cpu usage.

regards
Frímann

[gogalthorp]

I assume you are talking disk arrays????

Do users need direct access to the Disk Arrays or do they just support a Database.

if so isolate the disk arrays on their own net segment. Any machine that needs direct access to the arrays will have two NICs and live on both segments.

Why this massive copy? Sounds like a mirror configuration might be better if it is just a backup procedure.

I suggest a total rethink of your whole architecture.

[HROAdmin26]

rysnc manual

--bwlimit=KBPS limit I/O bandwidth; KBytes per second

Since this is on the same machine, make the connection using something like SSH - which will force rsync to use network sockets and thus the bwlimit.

Edit: Maybe the bwlimit would apply for any sync - try it and see.