On Tue, Apr 12, 2005 at 01:50:15PM -0400, Gene Heskett wrote:
> On Tuesday 12 April 2005 10:50, Salada, Duncan S. wrote:
> >Actually, I'm not using a holding disk at all.  I had no idea that I
> > could be shortening the life of the tape drive by not using one. 
> > So, that's probably the source of my problem then?
> The idea behind the holding disk (which really shouldn't be on the 
> same controller as the disk drive because of bus contention issues) 
> is that if the drive is waiting on data and stops, it will not 
> restart until the next file to be written is wholely in the holding 
> disk, at which point the copy can then take place at the drives 
> natural speed.

My current amanda server lives on one big 1.4TB partition on an SATA
hardware raid controller. Copying from the holding disk to file-tapes on
the same device has so far been limited to about 15MB/s. This seems
quite slow to me. Does amanda add any overhead above a simple copy on
the same device? An hdparm -t on this system when it's idle gives around
58MB/s.

I want to add a second SATA controller, fill up the remaining 4 drive
bays and move / and the holding disk to this separate raid. I expect
this set up will provide better performance. But, I want to ask if
anyone here has experience with a similar settup. Are there pci bus
limitations that would get in the way of the potential benefits? other
issues to consider?

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Eric Dantan Rzewnicki  |  Systems Administrator
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