Re: 2x Oracle slowdown from 2.2.16 to 2.4.4

[Brian Strand <bstrand@switchmanagement.com>]

Lance Larsh wrote:

>On Wed, 11 Jul 2001, Brian Strand wrote:
>
>>Our Oracle configuration is on reiserfs on lvm on Mylex.
>>
>I can pretty much tell you it's the reiser+lvm combination that is hurting
>you here.  At the 2.5 kernel summit a few months back, I reported that
>
Why did it get so much worse going from 2.2.16 to 2.4.4, with an 
otherwise-identical configuration?  We had reiserfs+lvm under 2.2.16 too.

>
>some of our servers experienced as much as 10-15x slowdown after we moved
>to 2.4.  As it turned out, the problem was that the new servers (with
>identical hardware to the old servers) were configured to use reiser+lvm,
>whereas the older servers were using ext2 without lvm.  When we rebuilt
>the new servers with ext2 alone, the problem disappeared.  (Note that we
>also tried reiserfs without lvm, which was 5-6x slower than ext2 without
>lvm.)
>
>I ran lots of iozone tests which illustrated a huge difference in write
>throughput between reiser and ext2.  Chris Mason sent me a patch which
>improved the reiser case (removing an unnecessary commit), but it was
>still noticeably slower than ext2.  Therefore I would recommend that
>at this time reiser should not be used for Oracle database files.
>
How do ext2+lvm, rawio+lvm, ext2 w/o lvm, and rawio w/o lvm compare in 
terms of Oracle performance?  I am going to try a migration if 2.4.6 
doesn't make everything better; do you have any suggestions as to the 
relative performance of each strategy?

Thanks,
Brian