[Box Backup] Controlling rate in lazy mode

[Martin Ebourne]

On Fri, 2004-10-08 at 11:09, Ben Summers wrote:
> >> On 8 Oct 2004, at 08:40, Adrian Cox wrote:
> >>> I'm using boxbackup on three Debian boxes. I've found that lazy mode 
> >>> is
> >>> really more like hyperactive mode, and the continual churning of the
> >>> disks has a noticeable effect on interactive use of the machine.
>
> > I do think an I/O throttle is a good idea, don't get me wrong.
> 
> Yes, but it's more to avoid swamping an internet connection while 
> people are working, rather than working around issues with your OS 
> failing to arbitrate between processes properly.

I have to say I don't have the problems originally described and I'm
running on Linux (FC2) using lazy mode. In fact I don't even notice that
its running while using the machine.

I'm only backing up about 4-5GB of data at the moment - maybe Adrian's
backing up large drives which change fairly often?

Two things to look at on Linux would be niceing the process, and maybe
altering the kernel swappiness control. This latter controls how keen
the kernel is to swap apps out to make space for disk cache and file
buffers. If you're scanning a lot of files once there's no point
swapping apps out to cache them, and for a desktop machine it's rare you
ever want to swap apps out for file caching. Personally all my
interactivity complaints with Linux went when I tuned it from the
default of 60 to 25, and it still makes good use of the swap partition.
(Google for 'swappiness' for more info)

Cheers,

Martin.