Logical Log File Rollover

We are using Dynamic Server, Version 7.30UC5, on Solaris. I am new to this version. My previous experience was on (I believe) 7.14UC3 on Irix. Under the earlier version, as log files filled up, I had to manually "spill" them to tape (or /dev/null) before they cold be reused, occasionally causing some system hangups when loading large, logged database tables. Under 7.30, I'm noticing entirely different behavior: It appears that Informix is willing to re-use (i.e., roll over to) a log file that has *not* yet been backed up to tape, given that the other log files are full. Can anyone confirm that Informix in fact made this kind of change, and confirm that my observation is correct? Many thanks. Rich -- Richard C. Auslander Database Manager AirFlash, Inc. 1733 Woodside Rd., Suite #110 Redwood City, CA 94061 (650) 556-7928 www.airflash.com

Richard, What you are probably used to seeing is the status of the backed up log changing from U to F. That no longer happens in 7.3x (or 7.2x for that matter). Now the flag will change from U-- (used, not backed up) to U-B (used and backed up, therefore ready for re-use). Doug Agnew Richard Auslander wrote in message <377A89BA.FA6C16BE@airflash.com>... >We are using Dynamic Server, Version 7.30UC5, on Solaris. I am new to >this version. My previous experience was on (I believe) 7.14UC3 on >Irix. Under the earlier version, as log files filled up, I had to >manually "spill" them to tape (or /dev/null) before they cold be reused, >occasionally causing some system hangups when loading large, logged >database tables. Under 7.30, I'm noticing entirely different behavior: >It appears that Informix is willing to re-use (i.e., roll over to) a log >file that has *not* yet been backed up to tape, given that the other log >files are full. Can anyone confirm that Informix in fact made this kind >of change, and confirm that my observation is correct? Many thanks. > >Rich >-- >Richard C. Auslander >Database Manager > >AirFlash, Inc. >1733 Woodside Rd., Suite #110 >Redwood City, CA 94061 >(650) 556-7928 > >www.airflash.com > >

Richard Auslander wrote: > > We are using Dynamic Server, Version 7.30UC5, on Solaris. I am new to > this version. My previous experience was on (I believe) 7.14UC3 on > Irix. Under the earlier version, as log files filled up, I had to > manually "spill" them to tape (or /dev/null) before they cold be reused, > occasionally causing some system hangups when loading large, logged > database tables. Under 7.30, I'm noticing entirely different behavior: > It appears that Informix is willing to re-use (i.e., roll over to) a log > file that has *not* yet been backed up to tape, given that the other log > files are full. Can anyone confirm that Informix in fact made this kind > of change, and confirm that my observation is correct? Many thanks. NO! The behavior has not changed at all. What has changed is that the onstat -l listing no longer list a log a status 'F' for free after ithas been backed up but 'U-B' for used but backed up. The status only becomes 'F' for an instance before the log is reused I have caught the onstat listing showing this only once or twice over the years. This was done so that you can look at your backed up logs with onlog as they are still there in a usable condition. This frequently confuses former V5.xx and V6.00 users when they move up to 7.xx. Art S. Kagel

Hi, Art ... (I'm kind a new to Informix) I have a follow-up question. We are currently using Informix-OnLine DS 7.24.UC6 under Solaris 2.5.1 and we have LTAPEDEV set to /dev/null. Now we wanted to implement a full enterprise backup procedures for our Informix-DB using the Legato Networker/onbar combination. Legato Networker requires that LTAPEDEV be set to something else other than /dev/null. As such, we set LTAPEDEV to another file name (/dev/logging), which is basically a soft link of /dev/null as our setup does not really require logical logging. Networker needs this to be different other than /dev/null for recovery purposes. Now my questions is, how do I make sure that automatic logging happens such that I don't have to issue any "ontape -a" or "ontape -c" for our logical log files. (Our db instance currently has a total of five logical log files with a size of 250 per log file.) That's all and thanks a lot in advance. Edwin M. Manalo UNIX Administrator COMCAST Cellular Coomunications, Inc. In article <377B7C8B.E85B521C@bloomberg.net>, kagel@bloomberg.net wrote: > Richard Auslander wrote: > > > > We are using Dynamic Server, Version 7.30UC5, on Solaris. I am new to > > this version. My previous experience was on (I believe) 7.14UC3 on > > Irix. Under the earlier version, as log files filled up, I had to > > manually "spill" them to tape (or /dev/null) before they cold be reused, > > occasionally causing some system hangups when loading large, logged > > database tables. Under 7.30, I'm noticing entirely different behavior: > > It appears that Informix is willing to re-use (i.e., roll over to) a log > > file that has *not* yet been backed up to tape, given that the other log > > files are full. Can anyone confirm that Informix in fact made this kind > > of change, and confirm that my observation is correct? Many thanks. > > NO! The behavior has not changed at all. What has changed is that the > onstat -l listing no longer list a log a status 'F' for free after it> has been backed up but 'U-B' for used but backed up. The status only > becomes 'F' for an instance before the log is reused I have caught the > onstat listing showing this only once or twice over the years. This > was done so that you can look at your backed up logs with onlog as they > are still there in a usable condition. This frequently confuses former > V5.xx and V6.00 users when they move up to 7.xx. > > Art S. Kagel > Sent via Deja.com http://www.deja.com/ Share what you know. Learn what you don't.

You can use the log_full.sh Informix delivers as the ALARMPROGRAM which will run an onbar each time a logfile fills up or you can get my eventalarm.c executable which currently does the same thing using ontape and make a few modifications to have it use onbar instead (I will probably be doing that version myself soon, actually) and you gain all of the event monitoring and notificaion that eventalarm performs for you also. Another option is to run onbar periodically from a crontab or if our legato is set up to wake periodically it can contact the engine and startup an onbar session itself using Legato's timers and alarms. You actually have a wealth of options. Art S. Kagel BTW: If this is a non-trivial instance you will need more logfiles for practical processing. I use 75 logs of 100000K each (7.5GB total). You may not need that much logging (we run a 700GB database) but you can get the point, your 1.25MB of logs is very small. manaloe@my-deja.com wrote: > > Hi, Art ... (I'm kind a new to Informix) > > I have a follow-up question. We are currently using Informix-OnLine DS > 7.24.UC6 under Solaris 2.5.1 and we have LTAPEDEV set to /dev/null. > Now we wanted to implement a full enterprise backup procedures for our > Informix-DB using the Legato Networker/onbar combination. Legato > Networker requires that LTAPEDEV be set to something else other than > /dev/null. As such, we set LTAPEDEV to another file name > (/dev/logging), which is basically a soft link of /dev/null as our > setup does not really require logical logging. Networker needs this to > be different other than /dev/null for recovery purposes. > > Now my questions is, how do I make sure that automatic logging happens > such that I don't have to issue any "ontape -a" or "ontape -c" for our > logical log files. (Our db instance currently has a total of five > logical log files with a size of 250 per log file.) > > That's all and thanks a lot in advance. > > Edwin M. Manalo > UNIX Administrator > COMCAST Cellular Coomunications, Inc. > > In article <377B7C8B.E85B521C@bloomberg.net>, > kagel@bloomberg.net wrote: > > Richard Auslander wrote: > > > > > > We are using Dynamic Server, Version 7.30UC5, on Solaris. I am new > to > > > this version. My previous experience was on (I believe) 7.14UC3 on > > > Irix. Under the earlier version, as log files filled up, I had to > > > manually "spill" them to tape (or /dev/null) before they cold be > reused, > > > occasionally causing some system hangups when loading large, logged > > > database tables. Under 7.30, I'm noticing entirely different > behavior: > > > It appears that Informix is willing to re-use (i.e., roll over to) > a log > > > file that has *not* yet been backed up to tape, given that the > other log > > > files are full. Can anyone confirm that Informix in fact made this > kind > > > of change, and confirm that my observation is correct? Many thanks. > > > > NO! The behavior has not changed at all. What has changed is that > the > > onstat -l listing no longer list a log a status 'F' for free after it> > has been backed up but 'U-B' for used but backed up. The status only > > becomes 'F' for an instance before the log is reused I have caught > the > > onstat listing showing this only once or twice over the years. This > > was done so that you can look at your backed up logs with onlog as > they > > are still there in a usable condition. This frequently confuses > former > > V5.xx and V6.00 users when they move up to 7.xx. > > > > Art S. Kagel > > > > Sent via Deja.com http://www.deja.com/ > Share what you know. Learn what you don't.