The reason I wrote this up was that it happened to me a couple of times. The first time I found out about it was one morning, on a 3 tape parallel backup. I noticed the backup had not finished, I did a RECALL and it wanted another tape. "O.K. this is expected to happen once in a while." So I put in the tape that it wanted. Methinks it was happy, until a minute later it says at the console it wanted a tape in the 2nd drive. O.K. I says again to myself, here's another. A minute later it wants a tape in the 3rd drive! Finally after putting in 3 new tapes, it RoadRunner starts writing. It wrote for a total of 5 minutes, then the job completed. The part that really hurt was it made my tape filing system unusual. Instead of the tapes being marked 1/3, 2/3 and 3/3; I had to mark them 1/2 of 1/3; 1/2 of 2/3, 1/3 of 3/3 the 2/2 of 1/3 then 2/2 of 2/3 and finally 2/2 of 3/3!. Worst case was 3 drives, it wanted another tape, so I did a recall, and it wanted a tape on BT NNNN Tracy Johnson MSI Schaevitz Sensors > -----Original Message----- > From: John Clogg [mailto:[log in to unmask]] > Sent: Monday, May 06, 2002 2:21 PM > To: [log in to unmask] > Subject: Re: [HP3000-L] Thinking about a new tape drive > > > Tracy's description of RoadRunner's behavior does not match > my experience > with the product. In fact it is quite rare for multiple > volumes to fill up > at the same time. We used RoadRunner for a number of years in an > environment with two tape drives. Three-tape backups were > quite common. > > I believe the way it works is that RoadRunner/Backpack > determines at the > outset which files will go to which drives. If all the files > destined for > one drive can fit on one volume, it won't ask for another one > on that drive, > even if the other drives require additional tapes. In our > case, we were > using the highest level of data compression, so the total > amount of data > written to each device was difficult to predict, often > resulting in uneven > distribution of the load among drives. In a situation where > the volume is > more predictable, I suppose the behavior Tracy describes is > more likely. > > -----Original Message----- > From: Johnson, Tracy [mailto:[log in to unmask]] > Sent: Monday, May 06, 2002 11:05 AM > To: [log in to unmask] > Subject: Re: Thinking about a new tape drive > > > The only drawback to performing the Parallel method, is that you must > monitor of how much tape is used over time. > > This is because when it goes *over-the-edge* (at least in > BackPack/RoadRunner) so it needs to write to more than the > number of tapes > specified, you're required to double the number of tapes used. > > i.e, > > If you write parallel to 2 tapes and the job wants more, even > if there is > only one more byte to go, you must insert 2 more tapes. > > If you write parallel to 3 tapes and the job wants more, even > if there is > only one more byte to go, you must insert 3 more tapes. > > <snip> > > * To join/leave the list, search archives, change list settings, * > * etc., please visit http://raven.utc.edu/archives/hp3000-l.html * > * To join/leave the list, search archives, change list settings, * * etc., please visit http://raven.utc.edu/archives/hp3000-l.html *