Since this didn't post last time:

Another good test to do would be one that measures simultaenous steaming 
read-write.   For example:

create table_a, with at least 10,000 records, where field1 is the PK and 
field2 is a text field.   
create table_b, with 500,000 or more records, where field2 is an FK to 
table_a, and field_3 is a text field.

do the following:

UPDATE table_b SET field3 = field3 || 'something'
WHERE EXISTS (select field1 FROM table_a
        where table_a.field1 = table_b.field2
        AND table_a.field_2 = 'x')

For the test to be most effective, the condition above should affect about 
100,000 records of table_a, and the records should not be contiguos on disk.  
Further, tablea.field2 should not be indexed in order to force a disk scan.

Also another test I'd really like to see is hardware raid (Adaptec, LSI) 
against Linux software raid, and 5-disk RAID 5 against 4-disk RAID 1+0.

-Josh Berkus
 Aglio Database Solutions
 San Francisco

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