topic Re: to modify or not to modify?? in Operating System - HP-UX

to modify or not to modify??

lastgreatone — Wed, 16 Jan 2002 23:27:41 GMT

An L-class was memory upgraded for a total of 1.5GB. There was/is intensive CPU hits on this system and block I/O contention. I reduced the dbc_max_pct. There are 2 swap areas on vg00 & vg01 of 896Mb ea at pri 1. The dba is recreating the instances that were configured at 2KB block size to 8KB. He doubled up the SGA buffer. Should I create another swap or modify current ones? If so, should I increase the maxswapchunks first, currently at default 1024?

Re: to modify or not to modify??

A. Clay Stephenson — Wed, 16 Jan 2002 23:44:52 GMT

Hi Frankie:

As a guess, I assume you are of the 2x MEM school for swap size. Assuming default swchunk size you can support 2GB of swap; I assume you want 3GB so set maxswapchunks to 1536. You can then add your swap partition. Please note that in a very real sense when you begin to talk about swap you are throwing performance out the window. Far better is to have enough memory so that you almost never swap.

Re: to modify or not to modify??

lastgreatone — Thu, 17 Jan 2002 14:09:56 GMT

Well I guess you just answered my question. I am of no particular 'set in the cement' type of school. But all reference material I've come across more or less, seem to emphasize rule of thumb for setting swap is 2x physical mem. I agree with you more memory the better especially with Oracle and I don't like using up disk space needlessly. So I will monitor performance and should I need to add another swap area I will. Thanks.

Re: to modify or not to modify??

harry d brown jr — Thu, 17 Jan 2002 14:16:18 GMT

Here's an oldie but stiff useful:

http://home.hanmir.com/~mjby/doc/oraunix.pdf

live free or die
harry