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:[EMAIL PROTECTED] > Sent: Tuesday, April 12, 2005 1:50 PM > To: [email protected] > 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. >
