On Monday 22 July 2002 16:47, Allan Sun wrote: >Hi all, > >I am new to Amanda and have just installed 2.4.2p2-1 on my > Mandrake 8.2(Kernel 2.4.18) .There is no problem to do a full > backup (I just did little change on the default setup),but I'm > not clear how to do daily incremental backup.I have HP DLT VS80 > external SCSI tape drive installed,which has no tape changer. > >Could somebody tell me how to do this?
This is generally left up to amanda. 4 things to consider: 1, amanda cannot append an incremental to an existing tape, so each run of amanda will need a different tape. Without a changer, this can be a daily chore that ocasionally gets forgotten. 2, with a suitable set of values in amanda.conf, amanda will virtually never do a full backup of the whole system in one swell foop. Amanda will adjust the scheduling to do about the same amount of data on each run instead. This has the effect of spreading the fulls around over the specified 'dumpcycle' period, doing a different set of entries in the disklist as fulls, and the rest as incrementals on any one night. 'dumpcycle' is often set to 1 week or 7 days. This guarantees a full of the whole system will be done during that time period. 'runspercycle' could be anything up to that same 7 days, and tells amanda how many runs she actually has to fit the above time constraint into. I presume that could be higher than the dumpcycle if you had a crontab entry that ran it twice a day for instance. But normally it gets run in the middle of the night so she can hog the system without bothering the users who may be awake that time of the night too much. 'tapecycle' is then set to the number of tapes in the storage pool. You should have them labeled sequentially within the constraints of whatever you set 'labelstr' to be in amanda.conf, and should have enough tapes to allow 2 full runspercycle of tapes to be run thru amanda plus a few spares. If tapecycle=runspercycle, then you would be over-writing the last good backup of something every night with no assurance that the newly made tape is a good tape. By haveing tapecycle >= 2*runspercycle, you are assured of having at least 2 (hopefully good) fulls of everything on hand at all times. I use runspercycle at 7 days, and tapecycle=20 here. 'runtapes' is normally set to 1, but could be more. I've not tried that at greater than 1 and actually had it used with the amount of data I have. 3, amanda cannot span a disklist entry to more than one tape, so adjust the sizes of the disklist entries to suit that constraint. She will if permitted goto the next tape, but that disklist entry's data that was in process when she had to goto the next tape will be restarted from the top on the next tape. So there is a possibility that it might use up all the tapes in the magazine if there is too much data for one tape in one entry of the disklist. 4, generally speaking, using the drives built-in compressor is a bad show. It hides the true capacity of the tape from amanda, which is a Bad Thing(tm). :-) First, you are stuck with it full time, and any already packed data you want to backup will grow when presented to that dumb compressor in the drive. Sometimes a _lot_. Second, most of our compression utils can very handily beat that hardware compressor at the compression game. Third, you can adjust each entry in your disklist to use, or not use, the compression available on the system. To start, use a backup profile that includes the use of 'client best' or 'server best' for all disklist entries and read the email from amanda when its done. Then reset to no compression for any disklist entry whose reported compression is over 100%, which indicates that the data actually grew. This will be your archived files collection probably because so far, a .bz2 file is about the best compression available, and it will grow quite a bit if re-compressed a second time. This isn't that much help I know, its more of a philosophical dissertation than specific help, but it addresses many of the newbieish 'make amanda do as I want' ideas. Amanda will do a better job when just given an outline of what she needs to do, and you leave the details of how its gets done to amanda. I note you have a DLT drive. That makes the tapes a lot more $$ than my DDS drive, one of the reasons I can afford to use amanda here at home. Howwever, there has been a lot of bashing of dat drives in general here on this list. Its been my experience that once a dat drive starts asking for a cleaning tape every 10 hours or so, its about past time to bin it. A DLT drive OTOH, should run longer, and should be a repairable item, the more expensive stuff usually is. Lastly, some operational improvements have been made to amanda since those rpms were built, so you might want to consider getting the latest snapshot tar's from Mr. Martinea's site at iro.umontreal.edu. I've been quite happy with the 2.4.3b3-20020702 snapshot here. There is also a gentleman here who is quite familiar with the rpms, and who will probably chime in with more specific help if the subject line mentions rpms. -- Cheers, Gene AMD K6-III@500mhz 320M Athlon1600XP@1400mhz 512M 99.08% setiathome rank, not too shabby for a WV hillbilly
