-----Original Message----- From: Unixboy@aol.com [mailto:Unixboy@aol.com] Sent: Thursday, August 10, 2000 1:37 PM To: Nelson.T.Caparrosso@mail.aas.ameritech.com Subject: Re: priority_paging and Veritas Quick I/O Please summarize this one. My initial thinking would be no, since you are bypassing the Kernel level IO and letting Veritas handle the IO for you. This would totally bypass a kernel level algorithym. Kris- -----Original Message----- From: Kevin Buterbaugh [mailto:Kevin.Buterbaugh@lifeway.com] Sent: Thursday, August 10, 2000 1:51 PM To: Caparrosso, Nelson T. Subject: Re: priority_paging and Veritas Quick I/O Nelson, What we've found is that it is not necessary to enable priority paging on database servers. (Note: we use Sybase). We give Sybase some amount of shared memory (generally around 150 -200 MB less than the amount of RAM installed in the box) with the remainder being for the OS. If there's nothing else generating significant filesystem I/O, the box rarely pages at all. On the other hand, on our non-database servers (we have a box that runs an application that (still) uses DISAM files, for example), we've found that enabling priority paging greatly improved performance. The main thing to make sure of before enabling priority paging is that data files don't have the execute bit set. That's how priority paging distinguishes between application executable and data files. Also, before upgrading a box to Solaris 2.8, be sure to remove priority paging, as 2.8 uses an entirely different memory architecture. Hope this helps... Kevin Buterbaugh LifeWay -----Original Message----- From: Shaun Irwin [mailto:sirwin@jcrew.com] Sent: Friday, August 11, 2000 5:23 PM To: Caparrosso, Nelson T. Subject: Re: priority_paging and Veritas Quick I/O FYI: What SUN tells me is "always" enable priority_paging regardless. It is most beneificial in oltp environments but will "never" hurt performance. I can't stand behind this other than to say I was told this from the instructor of the sun systems performance tuning class I recently took. Good Luck, -shaun