Re: Logical logs *newbie* question

On Tue, 11 Jul 2000 14:59:17 -0400, Gary Quiring <garyq@emcosales.com> wrote: Thank you for all of your help. I basically get it, I'm just unclear on how you would calculate how many logical logs and what size. We are planning to move our DB from SCO to SUN in August/Sept. It's a good time to redo anything that was mis-configured. Thanks Gary Q >We are running IDS 7.3. When I do an onstat -d there's only 206 free pages >available from a total of 75259. > >Here's what I don't understand. I do an entire backup ontape -s 0 over the >weekend when there's nobody using the system. After the backup the free >pages remains the same. If there's no transactions going on and the backup >has flagged the logs as being backed up, why does the free pages not get >larger? > >Thanks >Gary Quiring > > >onstat -d output: >Informix Dynamic Server Version 7.30.UC2 -- On-Line -- Up 4 days 23:17:22 >-- 3>23584 Kbytes > >Dbspaces >address number flags fchunk nchunks flags owner name >8fc4613c 1 1 1 1 N informix rootdbs >8fc47198 2 1 2 1 N informix data1dbs >8fc47254 3 1 3 3 N informix data2dbs >8fc47310 5 1 5 1 N informix data4dbs >8fc473cc 7 2001 7 1 N T informix tempdbs >8fc47488 8 1 8 1 N informix logdbs > 6 active, 2047 maximum > >Chunks >address chk/dbs offset size free bpages flags pathname >8fc461f8 1 1 0 100000 73515 PO- /dev/rrootdbs >8fc46b94 2 2 0 1024000 1023947 PO- /dev/rdata1dbs >8fc46c70 3 3 0 1024000 9007 PO- /dev/rdata2dbs >8fc46d4c 4 3 0 997997 600938 PO- /dev/rdata3dbs >8fc46e28 5 5 0 1024000 785866 PO- /dev/rdata4dbs >8fc46f04 6 3 0 1024000 1023997 PO- /dev/rdata5dbs >8fc46fe0 7 7 0 1024000 1022577 PO- /dev/rtempdbs >8fc470bc 8 8 0 75259 206 PO- /dev/rlogdbs > 8 active, 2047 maximum

Gary Quiring wrote: > > On Tue, 11 Jul 2000 14:59:17 -0400, Gary Quiring <garyq@emcosales.com> > wrote: > > Thank you for all of your help. I basically get it, I'm just unclear on > how you would calculate how many logical logs and what size. > > We are planning to move our DB from SCO to SUN in August/Sept. It's a good > time to redo anything that was mis-configured. Estimate the size of your largest acceptable transaction, note the number of pages affected and how (updates generate two logical log records, inserts and deletes one). Use this with the information about the size of logical log records in the Administrator's Guide (Vol 2????) and divide by LTXHWM as a percent to allow for the slack that that parameter forces you to have. Then add more space to allow for other transactions to be happening at the same time which will cause logs to fill also taking account of the running time of that large transaction. Decide how large you want each logfile to be so that it will be archived in a timely fashion by ontape/onbar as each fills, and then calculate how many logfiles of that size you will need. OR: buy a number of very large (18GB+) very fast (10,000RPM) drives and just fill them with logical log files until you cannot allocate any more. How much is peace of mind worth? $5,000US for 70-150GB of logical logspace? I think so. Art S. Kagel > Thanks > > Gary Q > > >We are running IDS 7.3. When I do an onstat -d there's only 206 free pages > >available from a total of 75259. > > > >Here's what I don't understand. I do an entire backup ontape -s 0 over the > >weekend when there's nobody using the system. After the backup the free > >pages remains the same. If there's no transactions going on and the backup > >has flagged the logs as being backed up, why does the free pages not get > >larger? > > > >Thanks > >Gary Quiring > > > > > >onstat -d output: > >Informix Dynamic Server Version 7.30.UC2 -- On-Line -- Up 4 days 23:17:22 > >-- 3> >23584 Kbytes > > > >Dbspaces > >address number flags fchunk nchunks flags owner name > >8fc4613c 1 1 1 1 N informix rootdbs > >8fc47198 2 1 2 1 N informix data1dbs > >8fc47254 3 1 3 3 N informix data2dbs > >8fc47310 5 1 5 1 N informix data4dbs > >8fc473cc 7 2001 7 1 N T informix tempdbs > >8fc47488 8 1 8 1 N informix logdbs > > 6 active, 2047 maximum > > > >Chunks > >address chk/dbs offset size free bpages flags pathname > >8fc461f8 1 1 0 100000 73515 PO- /dev/rrootdbs > >8fc46b94 2 2 0 1024000 1023947 PO- /dev/rdata1dbs > >8fc46c70 3 3 0 1024000 9007 PO- /dev/rdata2dbs > >8fc46d4c 4 3 0 997997 600938 PO- /dev/rdata3dbs > >8fc46e28 5 5 0 1024000 785866 PO- /dev/rdata4dbs > >8fc46f04 6 3 0 1024000 1023997 PO- /dev/rdata5dbs > >8fc46fe0 7 7 0 1024000 1022577 PO- /dev/rtempdbs > >8fc470bc 8 8 0 75259 206 PO- /dev/rlogdbs > > 8 active, 2047 maximum