2GByte chunk limit in Online 5.20

On Wed, 28 Jul 2004 10:36:11 -0400, Neil Truby wrote: Extending the offset capability is just a matter of using a 64bit compatible seek() function. Extending chunk size requires changing row and page addressing schemes. The latter changes lots of code, the former can be accomplished with a #define. Art S. Kagel > I learnt something this afternoon. We're preparing for an OnLine-on-Linux > installation tomorrow, and our client pointed out this link: > > http://www-306.ibm.com/software/data/informix/online5/extended/announcement.html > > where it states: > > "Support for greater than 2GB chunk offsets -- This performance-related > feature allows customers to utilize the entire capacity of the disk drive > without partitioning it into smaller logical devices and employing logical > volume managers. (blah blah, ROI, blah, blah .....)". > > And it's true! Although you still can't create chunks greater than 2Gbytes, > you can create multiple 2G chnuks in the same partition with ever-increasing > offsets. > > Which made me wonder: how does this work then? Surely the limits on > addressability apply equally to (chunk + offset) as (chunk)? (Although > evidently they don't!).

I learnt something this afternoon. We're preparing for an OnLine-on-Linux installation tomorrow, and our client pointed out this link: http://www-306.ibm.com/software/data/informix/online5/extended/announcement.html where it states: "Support for greater than 2GB chunk offsets -- This performance-related feature allows customers to utilize the entire capacity of the disk drive without partitioning it into smaller logical devices and employing logical volume managers. (blah blah, ROI, blah, blah .....)". And it's true! Although you still can't create chunks greater than 2Gbytes, you can create multiple 2G chnuks in the same partition with ever-increasing offsets. Which made me wonder: how does this work then? Surely the limits on addressability apply equally to (chunk + offset) as (chunk)? (Although evidently they don't!). -- Neil Truby t:01932 724027 Director m:07798 811708 Ardenta Limited e:neil.truby@ardenta.com

"Art S. Kagel" <kagel@bloomberg.net> wrote in message news:pan.2004.07.28.09.42.02.668809.1355@bloomberg.net... > On Wed, 28 Jul 2004 10:36:11 -0400, Neil Truby wrote: > > Extending the offset capability is just a matter of using a 64bit compatible > seek() function. Extending chunk size requires changing row and page > addressing schemes. The latter changes lots of code, the former can be > accomplished with a #define. > > Art S. Kagel Thanks Art, and Marco who explained the same thing. On this RedHat system, where there is no real limit on the number of partitions that a disk can have, I don't the >2GByte offset adds much, but it's all interesting stuff!