RE: Automated Continuous Log Backups?

Hi Keith, that's fine. Use what works for you. I didn't want to imply that everybody with a working environment should change it to fit my description. I rather meant to say that for somebody working on a new scheme (which was the original question), I would not recommend no-rewind devices as they have their pitfalls ... especially for those new to things or not exactly knowing what they do (like a standin admin when the guru is on vacation ...) Of course rewind devices also have pitfalls (like overwriting a tape). But these are better handled by ontape and described in detail in the manuals. Cheers, Martin -- Martin Fuerderer IBM Informix Development Munich, Germany Information Management informix-list-bounces@iiug.org wrote on 16.01.2006 16:14:17: > > I will bow to superior knowledge at this point, however > received wisdom has always said use a no-rewind device > (perhaps a hang-over from OnLine 5.x days). I am still using > no-rewind and have successfully restored and rolled forward > logs using the resulting tapes. Not got the time, inclination, > resource (or nerve) to try anything else at the moment. It > works, DON@T TOUCH IT !! > > Keith > > -> -----Original Message----- > -> From: Martin Fuerderer [mailto:MARTINFU@de.ibm.com] > -> Sent: Monday, January 16, 2006 2:04 PM > -> To: Simmons, Keith; Toby_AtkinsonSmythe@mailshack.com > -> Cc: Informix List (comp.databases.informix); > -> informix-list-bounces@iiug.org > -> Subject: RE: Automated Continuous Log Backups? > -> > -> > -> Hi, > -> > -> hmm. Not quite. > -> "ontape -c" is continuous log backup. It will backup logs as > -> soon as the server has switched to the next log, but it will > -> continue to write these logs to the same tape (or disk file), > -> until the tape (or file) is "full". It is full when the > -> amount of data > -> specified in onconfig parameter LTAPESIZE has been written. > -> At this point "ontape -c" will stop and prompt for a new tape > -> (or file). The user has to confirm the tape change was done > -> by pressing <RETURN> at ontape's prompt. Only after that > -> will ontape continue. > -> > -> Therefore it will work fine with rewind devices. > -> > -> In newer versions of ontape there's an additional check to > -> make sure that the old log tape is not overwritten. If user > -> pressed <RETURN> but the tape was not changed, then > -> ontape will detect this and refuse to write to this tape. > -> But with version 9.3x this probably is not your "concern" > -> as 9.3x is not among the "newer versions". > -> > -> "ontape -a" is different, as it will backup all the complete > -> log files that have not yet been backed up. It starts with > -> the oldest to keep the proper sequence. > -> Every time you start "ontape -a" it will start writing at the > -> beginning of a tape (therefore rewind devices are OK). > -> With files it will start at beginning of file, effectively overwrite > -> an existing file. With "ontape -a" I've not tested whether > -> the extra check for last tape is done. I assume it is done > -> (and "ontape -a" would refuse to overwrite it), but I'm not > -> 100% sure. But also "ontape -a" would prompt for a new > -> tape if a tape becomes "full" (as defined by LTAPESIZE), > -> if there is more log data to write than there's space on > -> tape/file. If there's no more data (all completed logs > -> backed up), than "ontape -a" will stop and exit. (Where > -> "ontape -c" would wait at this point for the next log to > -> complete). > -> > -> Using no-rewind devices (for real tapes) is possible, but > -> not recommended. I've talked to customers who > -> desperately tried to restore something and couldn't for a > -> week, only because they had forgotten that they have a > -> no-rewind tape and therefore needed to position the tape > -> manually ... > -> Files in the file system are treated like rewind devices. > -> > -> ON-Bar is quite different with all this mechanisms. You > -> might want to look into it, but to explain it all is too much > -> for an e-mail. > -> > -> Regards, > -> Martin > -> -- > -> Martin Fuerderer > -> IBM Informix Development Munich, Germany > -> Information Management > -> > -> informix-list-bounces@iiug.org wrote on 16.01.2006 10:11:30: > -> > Toby > -> > > -> > If I understand correctly you are using ontape -c to > -> backup tapes to > -> disk? > -> > This won't work as each time a log is backed up it will > -> overwrite the > -> disk file, > -> > ontape -c only works to a 'no rewind' tape device. Not > -> sure about ontape > -> -a > -> > (which writes all currently filled log files and then stops) but I > -> suspect it > -> > is the same. > -> > To write log files to disk you need to configure the > -> script pointed to > -> by > -> > ALARMPROGRAM to write each file to disk and then rename > -> the disk file to > -> prevent > -> > it being overwritten. there are example scripts provided, > -> or available > -> on the > -> > IIUG website. > -> > > -> > Keith > -> > > -> > -----Original Message----- > -> > From: Toby Atkinson-Smythe > [mailto:Toby_AtkinsonSmythe@mailshack.com] > > Sent: Saturday, January 07, 2006 9:21 AM > > To: Informix List (comp.databases.informix) > > Subject: Automated Continuous Log Backups? > > > > > > Can you possibly help? > > > > We are setting up a server with 4 or 5 small instances running IDS > 9.30.UC4 on Unixware 7.1.1 > > > > Due to the number of instances, the Logical Logs are written to disk as > they fill, and then archived to tape every evening. > > Is there a way to automatically and continuously backup the Logical Logs > to a file without tying up windows running ontape -c ? > > > > Yours in gratitude > > > > Toby