[kwlug-disc] rsync causing processor spike

Jonathan Poole jpoole at digitaljedi.ca
Fri Dec 6 15:49:10 EST 2013


How many files?  I like the --progress option (not sure if that is the right argument) 

Lots of files (millions) I've seen take a long time to calculate. 

Over ssh or just local?

Sent from my iPhone

> On Dec 6, 2013, at 3:45 PM, Chris Craig <kwlug.org at ciotog.net> wrote:
> 
> I wouldn't classify the rolling checksum used by rsync to be
> computationally expensive...
> 
>> On 6 December 2013 14:24, Paul Nijjar <paul_nijjar at yahoo.ca> wrote:
>> 
>> Rsync is computationally expensive if it thinks that it is sending
>> files remotely (because then it computes rolling checksums on all the
>> files, transfering only those parts that have changed).
>> 
>> I do not think that you are in that situation. However, you might try
>> the --whole-file (-W) option, which will transfer whole files without
>> computing checksums. This will probably be slower, but it might be
>> more lightweight.
>> 
>> If you are spiking the processor, then why is ionice the right tool to
>> use and not plain old nice?
>> 
>> - Paul
>> 
>>> On Fri, Dec 06, 2013 at 11:43:47AM -0500, Joe Wennechuk wrote:
>>> I am trying to rsync to an external drive on a running system; however, it is causing the processor to spike and bring down the webserver.
>>> I tried#> ionice -c3 -n19 rsync -vhr /dir/* /external/backup/
>>> but it still spikes the processor?
>> 
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>> 
>> --
>> http://pnijjar.freeshell.org
>> 
>> 
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