Re: Parameters LRU_MAX_DIRTY & LRU_MIN_DIRTY - UNIX

"John (Jack) O'Hara" wrote: > Our Informix Dynamic Server 7.22 running on Sun Solaris comes to a crawl > when usage reaches high levels. However, I've noticed that "SELECTS" > continue to be quick while UPDATES and INSERTS can take from 20 to 60 > seconds each. I noticed that our DBA has the LRU_MAX_DIRTY parameter > set to 2% and LRU_MIN_DIRTY set to 1% while Informix recommends defaults > as high as 60% and 50% respectively. The DBA insists this is not our > problem and refuses to even change these values a little. > IMHO, your DBA is right if you run an OLTP system. > > Has anyone had experience tuning these values? Am I correct to believe > that these values are forcing such a high rate of flushing dirty buffers > to disk that this unnecessary I/O is impacting UPDATES and INSERTS which > create dirty pages? > > Thanks for any help in this regard, > > Jack O'Hara > johara@writeme.com -- Arturo Rodr'guez Mutis Director de Inform'tica Melexa Ltda. PBX (571) 360 3055 FAX (571) 360 2562 e-mail melexa@colomsat.net.co