I do not claim to be familiar with the details of the NTFS file system
structure but if I remember from the manuals that covered formatting my
new harddrive back in the days when you upgraded PC rather than buy new
ones the 512k chunk on disk was the device sector size. The OS
however, reads and writes multiple secotrs at a time. This grouping of
sectors was called a cluster and generally was 2k, 4k, or 8k worth of
sectors at a time. On any other system except Windows the cluster size
would be called the block size. The cluster size dedended on the
size/mdoel of the disk drive and how it was partitioned.
If the OS block size is 4K the two OS IO are required for every Oracle
IO and 25% of the IO is wasted since it is not part of the requested
Oralce block(s). This would be bad. If on the other hand the OS IO
size is 6k then the 6k size choice for Oracle was probably a good one
in the past. Since the manuals refer to Oracle only officially
supporting 4k, 8k, 16k, and 32k you may want to determine what the real
OS IO size is and match the database to it.
Received on Sun Apr 03 2005 - 12:38:33 CDT
