Actually, you have not said a word about which controllers you use (for
the drives).  Using the wrong controller can drain speed a lot.  As from
the kernel benchmarks it seems like neither RAM nor computing power are
the bottlenecks.

Some SATA-controllers handle "nearly parallel" writes to multiple drives
better than others.  SiI products for example have a noticeable drop-off
for each disk you add.  Pretty late Intels nearly show no impact of many
disks in parallel.  So maybe that could be the topic you should be
after.  (And maybe a lspci could help :)

Stefan

Hi Stefan,

Here is the output of lspci.  There are 5 disks on the ATI controller. 
Four of them are part of the RAID.  The last disk is on the JMicron
controller which is a PCIE-1x card.  I can move one more disk to the
JMicron controller if you think that would help.  Or just purchase a new 4
port controller?

lspci|grep SATA
00:11.0 SATA controller: ATI Technologies Inc SB700/SB800 SATA Controller
[IDE mode]
02:00.0 SATA controller: JMicron Technologies, Inc. 20360/20363 Serial ATA
Controller (rev 03)

---
Will Y.


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