O.K., I was trying to understand why the performance for Oracle was poor
with RAID0. With no raid and 8 files 2GB each, across 4 SCSI disks and two
scsi hosts; an import of 1GB + analyze runs for 4 hours. With raid0 i killed
the process after 8 hours.
The machine is a HP LH4, two Xeon 400Mhz, with two ncr53c8xx scsi hosts
and 6 UW2 disks of 9GB each, kernel 2.2.5 and raidtools 0.9. The raid0 is
composed by 5 full disks, and i tryed chunk-sizes 4K,16K,32K,128k and 256K,
mke2fs -b 4096 -R stride=(chunk-size/4096); but performance for import was
always poor.
any ideas?
Thanks, Eladio.
Eric Ladner wrote:
> The db_block_size is not the size that oracle reads or writes in the
> manner that you are thinking. From the OS level, that is still based on
> the IO routines of the host operating system.
>
> The db_block_size is the minimum allocation size on the MEDIA. i.e. if
> you have a device that the block size is 4K, you don't want to put 2K
> blocks on it, but 4K instead.
>
> This parameter is usually OS driven and typically doesn't have much to do
> with the database at all. On Linux, I'd pick 8K as a decent size...
>
> Eric
>
