RE: TAPEDEV or -t STDIO?

I understand that /dev/null bypasses the backup and doesn't actually perform any archive at all, but the manual also says that: "The -t STDIO option overrides the value of the TAPEDEV configuration parameter for the current backup." http://publib.boulder.ibm.com/infocenter/idshelp/v10/index.jsp?topic=/com. ibm.bar.doc/barmst282.htm ** BTW this link is for v10 (as specified in my original post), not v115 ** So, if using -t STDIO causes the server to OVERRIDE the value of TAPEDEV and I'm using -t STDIO > /dev/null, shouldn't either method, theoretically, do the same thing and perform the same way? However, my question still remains (aside from /dev/null) - when using ontape to perform a backup to a file, is there any difference (specifically performance-wise) between specifying the filename in TAPEDEV and using -t STDIO filename? Thanks! Brian >-----Original Message----- >From: Clive Eisen [mailto:clive@serendipita.com] >Sent: Friday, August 13, 2010 11:39 AM >To: Brian Amstutz; informix-list@iiug.org >Subject: Re: TAPEDEV or -t STDIO? > >On 13/08/2010 16:16, Brian Amstutz wrote: >> HP-UX 11i v2 >> Informix 10.00.FC9 >> >> ontape -s -L 0 with TAPEDEV set to /dev/null takes 2 seconds or less >> ontape -s -L 0 -t STDIO> /dev/null still running after 30 minutes>> >> Besides the question of "why" is it so much longer when using -t STDIO, my >> real question is if this archive were to a "real" file (instead of >> /dev/null), would the time difference be significantly longer as well - >> i.e. would using -t STDIO> <somefile> take significantly longer than >> setting TAPEDEV to<somefile>? > >er RTFM? > >http://publib.boulder.ibm.com/infocenter/idshelp/v115/topic/com.ibm.bar.d oc/ids_bar_455 >.htm > >specifically > >When you set TAPEDEV to /dev/null and request a backup, the database >server bypasses the backup but still updates the dbspaces with the new >backup time stamps. > >-- >Clive > >-- >This message has been scanned for viruses and >dangerous content by OpenProtect(http://www.openprotect.com), and is >believed to be clean.

On Aug 13, 3:32 pm, "Brian Amstutz" <brian.amst...@asburyseminary.edu> wrote: > I understand that /dev/null bypasses the backup and doesn't actually > perform any archive at all, but the manual also says that: > > "The -t STDIO option overrides the value of the TAPEDEV configuration > parameter for the current backup." > > http://publib.boulder.ibm.com/infocenter/idshelp/v10/index.jsp?topic=.... > ibm.bar.doc/barmst282.htm > > ** BTW this link is for v10 (as specified in my original post), not v115 > ** > > So, if using -t STDIO causes the server to OVERRIDE the value of TAPEDEV > and I'm using -t STDIO > /dev/null, shouldn't either method, > theoretically, do the same thing and perform the same way? > > However, my question still remains (aside from /dev/null) - when using > ontape to perform a backup to a file, is there any difference > (specifically performance-wise) between specifying the filename in TAPEDEV > and using -t STDIO filename? Brian, When you set TAPEDEV to /dev/null, then ontape is able to read the onconfig file, and thus knows that the backup is a NULL backup. When you use -t STDIO > /dev/null, then ontape is not aware of the final disposition of the backup. It only knows that it was requested to pass the backup data to an output file via stdout. It does not no that stdout is being directed to /dev/null. Only the shell knows that. M.P. > > Thanks! > > Brian > > > > >-----Original Message----- > >From: Clive Eisen [mailto:cl...@serendipita.com] > >Sent: Friday, August 13, 2010 11:39 AM > >To: Brian Amstutz; informix-l...@iiug.org > >Subject: Re: TAPEDEV or -t STDIO? > > >On 13/08/2010 16:16, Brian Amstutz wrote: > >> HP-UX 11i v2 > >> Informix 10.00.FC9 > > >> ontape -s -L 0 with TAPEDEV set to /dev/null takes 2 seconds or less > >> ontape -s -L 0 -t STDIO>  /dev/null still running after 30 minutes> > >> Besides the question of "why" is it so much longer when using -t STDIO, > my > >> real question is if this archive were to a "real" file (instead of > >> /dev/null), would the time difference be significantly longer as well - > >> i.e. would using -t STDIO>  <somefile>  take significantly longer than > >> setting TAPEDEV to<somefile>? > > >er RTFM? > > >http://publib.boulder.ibm.com/infocenter/idshelp/v115/topic/com.ibm.b... > oc/ids_bar_455 > >.htm > > >specifically > > >When you set TAPEDEV to /dev/null and request a backup, the database > >server bypasses the backup but still updates the dbspaces with the new > >backup time stamps. > > >-- > >Clive > > >-- > >This message has been scanned for viruses and > >dangerous content by OpenProtect(http://www.openprotect.com), and is > >believed to be clean.