Re: PHISICAL LOGS configuration

Mauro G. Pisano wrote: > > Hi: I am tryin to improve perfomance in our environment. We have On-line 5.0. > The On-line Administrator Guide recommends to define the phisical logs size > twice the logical logs size. Other rule is to define both size with a > relation 3:1 logical logs vs phisical logs. If I follow this I always have > six logical logs. I have 5 GB of disk space for Informix. 1 GB is for the > root dbspace and the other 4 GB. for the others chunks. > > Here are my questions : > > 1. Is the disk space well managed ? It is in a well tuned system. But if you don't set things like extent sizes correctly, then you can end up with a fragmented system. > 2. wich is the On-line's space, is all the space or only the root > dbspace's space ? All dbspaces. > 3.shoul I prefer few and large logical logs or many and small ones ? Generally many and small, BUT, don't make them TOO small. Also, if your physical log is too small you can have performance problems. When the physical log is 75% full a checkpoint is fired. This is a big overhead on the system, so if check points are firing too frequently (ie. your physical log is too small) you will have performance problems. Hope this helps, -- Mark. +-------------------------------------------------------------------------+ |Mark D. Stock - The West Solutions Group http://www.west.co.za | | The Informix FAQ is at http://www.iiug.org | |mailto:marks@west.co.za +------------------------------------------------+ |Tel: +27 11 803 2151 |If it doesn't work... force it! | |Fax: +27 11 803 2189 |If it breaks... it needed replacing anyway! | |Cell: +27 83 250 2325 |Well, that's how I code anyway! | +------------------------+------------------------------------------------+