Due to the IBM implementation of reads for JFS database files, Sybase IQ performance improves if you create dbspaces on each disk, instead of creating one large file. Smaller files allow Sybase IQ to handle disk I/O operations much more efficiently, especially when combined with disk striping and possibly multiple controllers.
Currently Sybase recommends that you create three files per underlying disk drive.
When setting up raw partitions, the system administrator specifies the sector size, which defines the minimum usable chunk of disk (and sets the minimum Sybase IQ block size). When you use raw partitions, the integer you specify as a block size for Sybase IQ must be a multiple of the sector size. The System Administration Guide: Volume 1 provides details on specifying block size.
