what should be the fit size for a chunk

IDS 9.4 have a ability to create a chunk to 4T,in informix document, It recommend that one dbsapce one chunk. if I have a 100G database, It is better way for me create a dbspace and just alloc a chunk in 100G? another question: I have a informix server in AIX,and I want to create a raw device (LV) for the Informix server,the raw device (LV) base on a vg ,which pp size is 32M,it is better way to recreate this vg and set the pp size to 128M -- Posted via http://dbforums.com

See below... "dusong" <member21945@dbforums.com> wrote in message news:3093679.1057806860@dbforums.com... > > IDS 9.4 have a ability to create a chunk to 4T,in informix document, > It recommend that one dbsapce one chunk. if I have a 100G database, > It is better way for me create a dbspace and just alloc a chunk in 100G? I hope that we don't recommend one chunk per dbspace. I don't think that is the intention. I think that the intention is simply to state that the new max size chunk is 4TB and that the max size of a single dbspace is also 4TB. There is a bit of an advantage if you only have one chunk per physical disk because IOs during checkpoints are scheduled by chunk. Therefor, you can minimize disk contention. However, this advantage does not really exist if you are using disk striping or RAID-5. Also, if you are using a logical volumn manager and the logical disk is spread accross multiple physical disks, then I don't think you would see the advantage. > > > another question: > > I have a informix server in AIX,and I want to create a > raw device > (LV) for the Informix server,the raw device (LV) base on a vg > ,which > pp size is 32M,it is better way to recreate this vg and set > the pp size > to 128M > > -- > Posted via http://dbforums.com