Cleaners-Mirror and Temporary Chunks
The number of Cleaner's does not only depend on the number of disk but also the the number of LRU Queues (LRU). You should then set you Cleaner value to the number of Disk that are updated during a checkpoint only if LRUS is not set to a higher value, otherwise use the same value that you have for LRU. But you should not add your chunks in successive order if the chunks will be spread across more then one disk. Due to Cleaner Performance reasons. For example: Let's say you will be creating 4 chunks that will be using two different disk. Then it is best to create chunks 1 and 3 on the same disk and 2 and 4 on the other. This only applies if the CLEANERS are still accessing the disk as they do in Online 5.X (which is in a round robin fashion). This also applies to how you should create your Logs. So essentially the number of chunks is not what you consider but the number of DISK and the VALUE of LRU. C.L. Kendricks vnibs2@heb.com --------------------------( Forwarded letter 1 follows )--------------------- }Date: Thursday, 6 March 1997 7:16am }From: Milan.Vesely@mzcr.cz }Subject: Cleaners-Mirror and Temporary Chunks }Date:Thu, 6 Mar 1997 12:48:20 -0600 }Reply-To: Milan Vesely <Milan.Vesely@mzcr.cz> }Organization: Ministry of Health }Sender: informix-list-owner@rmy.emory.edu }To: informix-list@rmy.emory.edu }X-Informix-List-Id: <news.34847> } }According to Informix chunks should be added to system }in a successive way - to be cleaned correctly by }CLEANERS. The number of CLEANERS should be the same }as the number of disks to be cleaned. }But: How to consider TEMPORARY and MIRROR chunks? } Should I take them into account or not? } If I have a TEMPORARY dbspace on a separate disk } and a MIRROR chunk on another separate disk, } should I add these TEMPORARY and MIRROR chunks } in a successive way as mentioned above and } should I increase number of CLEANERS by 2 ? }(We have Informix Online v.7.13 and all data is on raw } partitions). }Thanks very much for any help. }-------------------------------------- }Milan Vesely }Ministry Of Health Czech Republic }Palackeho nam. 4 }Praha 2 }tel. 02/2497 2182 }fax. 02/2491 6019 }e-mail: Milan.Vesely@mzcr.cz