Re: Chunk writes

The server assigns page cleaner threads to a particular chunk in the database in the order the chunks were defined. In order to ensure they work on different disks, create chunks in the order you want the cleaners to be assigned. This is from the Informix training manual for "System Administration", a course I highly recommend. (Version 08-98, page 9-285.) Clem At 11:29 PM 22-03-99 GMT, gheppes@my-dejanews.com wrote: >Hi, > >I am in the process of creating the layout for a database. I will have 6 >physical disks to work with (plus another 6 for mirroring). I understand that >CLEANERS should be set to the number of disks, in this case 6. I also gather >from messages that this scheme would perform optimally if I had one chunk on >each disk and would have roughly the same number of updates on each. As I >will have to work with 9GB disks I will have to place at least 5 chunks per >disk. How can I make sure that 5 of the cleaners will not be working on the >same disk at one time? How are chunks allocated to the cleaners, by chunk >numbers? > >Which brings me to another question... Does the server look at the pathname >of the chunks in it's attempt at trying to sort writes? What I'm trying to >get at is whether it makes any difference how you allocate chunks from a >performance point of view: is it better to define multiple chunks in one (max >2GB) file with offsets - in which case all of these chunks will share the >same pathname - or better to have a separate file (logical volume on AIX) for >each chunk? > >TIA > >Gabor Heppes ><gaborh@au1.ibm.com> _______________________________________________________________ Clem Akins (aka clem@informix.com) Menlo Park x5937 Customer Course Development Informix Software, Inc Last seen: Back in Menlo Park at the NorCal User Group Meeting