--On Monday, November 11, 2002 09:12:33 +0100 Nicolas Cartron <[EMAIL PROTECTED]> wrote: >> You are living dangerously with your current setup. Each time >> you write a tape you are overwriting the only copy of your data. >> If you ever have a tape error you have nothing to restore from. >> And if you need a file that was deleted the day before your full >> but wasn't new enough to be on your incremental then you are out >> of luck. > > not really, in fact the datas are truncated to the previous datas, > i.e. the tape continues recording where it stopped. > Am I wrong ?
Maybe I misinterpreted your setup. What I thought you were doing is using a total of 2 tapes. One tape would get a full backup of everything written on it. The other would get incrementals written to it the next day, and would stay in the drive the rest of the week with each day's incrementals appended to it. If that is the case, then it works as long as nothing goes wrong. However, when (not if) there is a problem, then you have little or nothing to restore. If the tape server would happen to reboot during the week the tape would most likely get rewound and the next incremental run would overwrite all the previous ones. If an error occurs during the full backups, you have no full backups to restore from since you were in the process of overwriting your last good one. Also, when a tape read error occurs, you won't have an older tape to at least restore some of the files from. >> Amanda wasn't really designed for the all fulls on one night >> incrementals every other night schedule. It can be forced to do it that >> way but it takes more work to set it up like that. The idea of Amanda >> is to spread the fulls and incrementals around so as to use about the >> same amount of tape on each run. > > Can you explain me what you mean by > 'spread the fulls and incrementals around' ? For a simple case, assume you back up 7 filesystems that are each about the same size and have about the same amount of changes each day, and Amanda runs 7 days a week with a dumpcycle of 7 days. You would probably end up with one full backup and 6 incrementals on each day's tape, so each day about the same amount of tape would be used. Even when you add filesytems or have unusual amounts of data changes, Amanda will postpone some full dumps, change dump levels, and move ahead other full dumps in order to keep the tape size about the same so you won't run out of tape on those days. With the more traditional 'full on weekend, incremental weekdays' approach you end up with a huge run doing the fulls, and very small runs during the weekdays, so most of your tape capacity goes unused (except in your case where you do appends to one tape, but that has other issues). Frank -- Frank Smith [EMAIL PROTECTED] Systems Administrator Voice: 512-374-4673 Hoover's Online Fax: 512-374-4501
