Yeechang Lee wrote:

A few performance-related questions:

* What chunk size should I use? In previous RAID 5 arrays I've built
for similar purposes I've used 512K. For the setup I'm describing,
should I go bigger? Smaller?


It is best to try a number of different configurations and benchmark
each one to see how it works with your needs. For my needs I've mainly
used 64 KB stripes because it gave better performance than 128 or
higher. Make sure you match the file system chunk size to the RAID
stripe size too.

* Should I stick with the default of 0.4% of the array as given over
to the JFS journal? If I can safely go smaller without a
rebuilding-performance penalty, I'd like to. Conversely, if a larger
journal is recommended, I can do that.


I'd probably just keep it at the defaults.

* I'm wondering whether I should have ordered two RocketRAID 2220
(each with eight SATA ports) instead of the 2240. Would two cards,
each in a PCI-X slot, perform better? I'll be using the Supermicro
X7DVL-E
(URL:http://www.supermicro.com/products/motherboard/Xeon1333/5000V/X7DVL-E.cfm)
as the motherboard.



As Scott mentioned, since it looks like this MB has both slots sharing
the PCI-X bus it probably wouldn't help to separate them out unless the
architecture of the card has limitations. Even if they were separate
buses though I don't think it would help you to have two cards since the
bandwidth of the bus exceeds the needs of the drives.

For this many SATA drives I would hope that you are going with RAID6 and
a hot-spare.

Steve