Thanks for the info, Gene.  That will be very helpful when telling folks why 
the disk is needed and when I set it up.

Duncan

-----------------------------------------------
Duncan Salada
Titan Corporation
301-925-3222 x375


> -----Original Message-----
> From: Gene Heskett [mailto:gene.heskett AT verizon DOT net]
> Sent: Tuesday, April 12, 2005 1:50 PM
> To: amanda-users AT amanda DOT org
> Subject: Re: slow client
> 
> 
> 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?
> 
> I expect it is, Duncan.  One really should have a holding disk area 
> that is capable of holding the 2 or 3 largest disklist entries, 
> preferably lots more, and thats easy when todays commodity drive is a 
> 120GB or so drive.  I have about a 25GB area, free space on a 
> partition and this, for the dle's I have constructed, is only used to 
> maybe the 22GB free at its peak use.  But then I've tried to follow 
> my own advice in that most of my disklist entries (nearly 50 of them) 
> are all fairly smallish, giving amanda as much help in her balanceing 
> action as possible.
> 
> 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.
> 
> By carefull choice of the priority string in your 
> amanda.conf, one can 
> often hit a point where once the drive starts, it will run non-stop 
> until the nightly run is done.  I try to put the biggest ones on the 
> front of the tape, and by the time the first one is cached and 
> written, many of the rest are waiting, so the drive never stops 
> between files.
> 
> Shoe-shining the drive because its running out of data, making it 
> stop, backup to the last good block written, & repeat at 2 (or less) 
> second intervals, is very hard on both the drives mechanics and the 
> heads, but is also making a one pass write into a many pass write, 
> with a severe reduction in the life of the tape.
> 
> When you do setup the holding disk, be sure and add a line in your 
> amanda.conf thats says something like 'reserved 30%', otherwise it 
> can only be used in the event of a tape problem for incrementals, no 
> fulls.  With it in there, then fulls can proceed as normal, piling up 
> in the holding area until its down to 30% of its original capacity 
> remaining.  It might give you an extra day or 2 to solve a tape drive 
> problem in that event.
> 
> [...]
> 
> -- 
> Cheers Duncan, 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.
>