On Tuesday 12 April 2005 14:23, Eric Dantan Rzewnicki wrote:
>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.
Considering that the data has to go both ways up and down the cable,
that may be about the practical limit.
> 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?
The stock pci bus is pretty well tapped out at 132 mhz, pci-x can
quadruple that.
--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
99.34% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2005 by Maurice Eugene Heskett, all rights reserved.
|
