Norbert Martin wrote: >Thats very easy. >Incremental, on default, is: The last active Backup Version of a Backup. >That true if you want to restore the last >incremental 1,2,3,4,5...+ Full Backup state of your server. > >By using incrbydate, you can select the backups by date, for sample befor 30 >days. All modification on a certain day. > >hope this helps > >regards norbert > >P.S: It's not nice to know who writes > > >-----Urspr|ngliche Nachricht----- >Von: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED]]Im Auftrag von >Fc-Atm-Rck, Tivoli (UNKNOWN) >Gesendet: Friday, August 09, 2002 12:28 AM >An: [EMAIL PROTECTED] >Betreff: incremental and incremental -incrbydate > > >What exactly is the different between running backups with incremental and >incremental -incrbydate? > >Thank you. > > Norbert and who ever posted the original question,
I am sorry Norbert but your explanation of incrbydate is horribly wrong. In fact you definition of incremental isn't even right. When TSM does a incremental backup it selects files based on then being either a new or changed file. This is relative to the information that is kept in the TSM data base versus what is actually on the clients machine. Now there are several parameters which determine whether a file has changed, i.e. data modified, permissions changed, ownership changed, etc. We also note when a file has been deleted during this process as well. This is the preferred method for doing your regularly scheduled backups. In addition Norbert, in you explanation refer to "incremental 1,2,3,4,5...+ Full Backup", TSM does nothing of the sort! The old expression for how TSM did backups was "incremental forever", however that is not in fact accurate either the preferred terminology today is "Progressive Backup Methodology". We truly do not do full and incrementals in the classic sense at all! Now in regards to incrbydate, that is effectively a very limited version of a incremental backup. It's only advantage is that it will reduce that backup time for the client, but it does come at a cost. It uses a reduced set of criteria to determine whether a file gets backed up. The only criteria it uses is the files data modification time stamp (remember on some OS's there are multiple time stamps for a file). It compares this time stamp to a time stamp kept in the TSM DB for the particular file space that the file resides in. The file space time stamped is set every time you do a complete ( as opposed to a partial using a filespec, i.e. Incremental /home/mark/*, when the filespace is /home) incremental backup. Another unfortunate side effect of the incrbydate option is that it does not note deleted files. In addition, a new file moved into the filespace but having a modification time stamp earlier then the last complete incremental backup will not be backed up. Another side effect is if you attempt to do a point in time (PIT) restore it will always roll back in time to the previous complete incremental. BTW, include/exclude lists get processed exactly the same for either command. The long and short of it, incrbydate should only be used if your backup window does not allow you to do a regular complete incremental backup. However if you choose to use this option you MUST still do regular complete incrementals on some regular schedule. Norbert, I do not mean to flame in you in any way with this note and I apologize if you are offended by this. I am sure you did not intend to be misleading, but I could not let this misinformation go uncorrected. -- Regards, Mark D. Rodriguez President MDR Consulting, Inc. =============================================================================== MDR Consulting The very best in Technical Training and Consulting. IBM Advanced Business Partner SAIR Linux and GNU Authorized Center for Education IBM Certified Advanced Technical Expert, CATE AIX Support and Performance Tuning, RS6000 SP, TSM/ADSM and Linux Red Hat Certified Engineer, RHCE ===============================================================================
