max_io_size on Solaris 2.6 UFS

From: Bits 'n' Bytes <leaman_at_shell.clark.net>
Date: 6 Oct 1998 03:03:03 GMT
Message-ID: <6vc197$9eh$1@clarknet.clark.net>

I'm trying to configure a large max_io_size on an Oracle 7.3.3.6 system running Solaris 2.6. db_block_size is 16K, and when I set db_file_multiblock_read_count above 8, Oracle throttles it back to 8 such that the block_size*read_count=128K. I've increased the maxphys, ufs_HW, and ufs_LW kernel parameters in hopes that it would get me around the 128K limit, but it hasn't helped. Is this *still* a bug in Oracle, or am I missing something? I'm using UFS filesystems. Could it be that larger I/Os are only supported with raw devices?

How does Oracle determine the maximum I/O size that is supported by the underlying operating system?

Bryan S. Leaman
Systems Engineer
leaman_at_bitbytes.com Received on Mon Oct 05 1998 - 22:03:03 CDT