On Wednesday 07 January 2004 07:28, Dean Pullen wrote: >Hi again. > >I've been using amdump manually to test Amanda, and am backing up a > full disk's file system (/dev/sda). The first time its run it > produces a report with several gigabytes worth of backup: > >USAGE BY TAPE: > Label Time Size % Nb > VFDailySet01 0:08 3393.4 4.1 1 > >Repeating runs on the same tape after this backup, seems to produce > very tiny backups: > >USAGE BY TAPE: > Label Time Size % Nb > VFDailySet01 0:00 0.2 0.0 1 > >Does amanda only save 'changes' to files, or is something incorrect >happening here? > >Dean
You cannot rerun on the same tape *until* that tape comes back around in the tapelist. And if you force it, the previous backup on that tape WILL be lost. Amanda, by design, cannot append to a previous runs tape. It must have total control over the tape for the duration of each run, which is why you must use a non-rewinding device with it. It can use more than one tape per session, but cannot span one disklist entries data over more than one tape. In the event an EOT is hit, it will go on to the next tape if you have the robotics to do so, but the failed tarfile it was writing at the time will be restarted from the beginning on the next tape. The length of the tapelist is a function of the "tapecycle" variable in your /config/dir/path/amanda.conf. Amanda keeps records of what has been backed up, and until "dumpcycle" time has expired, won't (normally, there are exceptions that will occur while amanda is adjusting the schedule to get in "balance") do another full on that file, only incrementals. Amandas scheduler is actually pretty intelligent, but doesn't often let you see it other than an occasional overview, most of the decision makeing is done on the fly after getting the estimates. You need to re-read the docs and get the amanda 'way of doing things' better fixed in your view of how a backup works. Some programs may try and make things work by hand, but this really isn't amanda's normal way of doing things, it is geared for one run per day only for starters as its overall time stamps are based on a 1 run per day situation. More than 1 run will just confuse amanda. BRU (bring money) and Arkeia (bring LOTS more money), may be able to do it but AIR arkeia also doesn't like more than 1 run unless the data being backed up is all different. This is usually done by putting the amanda invocation in the user amanda's crontab file so its run in the early wee hours. It doesn't need nor want any human intervention while its running. Your job is to see to it that amanda is fed the right tape at the right time, and having done that, to get a good nights sleep knowing amanda is on the job. Amanda, to run well, will need a bit more "holding disk" space than runtapes x tapesize, if its to do a full run, but finds the wrong tape and doesn't write it out to the tape. Thats a case where you would read the email from amanda telling you about it the next morning, put in the right tape and run amflush to catch it up. In this manner, nothing is lost if the operator is off duty or forgets. Amanda is a heck of a lady, but it takes some study to really get to know her. :-) -- Cheers, Gene AMD [EMAIL PROTECTED] 320M [EMAIL PROTECTED] 512M 99.22% setiathome rank, not too shabby for a WV hillbilly Yahoo.com attornies please note, additions to this message by Gene Heskett are: Copyright 2003 by Maurice Eugene Heskett, all rights reserved.
