On Jul 21, 2009, at 6:25 AM, F. Wessels wrote:
So to wrap it up. According to Will, a supermicro chassis using a
single lsi expander connected to sata disks can utilize the wide sas
port between hba and the chassis. (like a J4500 Richard mentioned.
How much I like these systems (thumper etc), they're way out of my
budget.) Will did see more throughput than a single link could
handle. But due to insufficient disks no more i/o could be generated
to better demonstrate the availability off the wide sas port.
I assume the J4500 is using dual expanders. Richard, can you confirm
that the J4500 is using an active/active sata mux per drive to allow
failover between expanders?
Yes, this is seen in Figure 1-1 of the Sun Storage J4500 Array
System Overview manual. Look for the Active-Active MUX (AAMUX).
http://dlc.sun.com/pdf/820-3163-11/820-3163-11.pdf
Aside from this can you also confirm that a wide sas link between a
hba and a single expander can be fully utilized when using sata
drives? To rephrase, utilization is independent of the disk type
(sas or sata)
It is a simple architecture. Think of expanders (and AAMUXes for this
case)
as switches, and it might seem more familiar. For a dual-port SAS disk,
that Sun only sells in 2.5" form factor (IIRC), you don't need the
AAMUX.
For example, the J4400 is basically the same architecture as the J4500,
except that it accepts SAS and SATA disks. Since there is a mix, it is
not
feasible to put the AAMUX on the system board, so they are placed in
the disk carrier. If you look at the exploded part numbers, you'll see a
SATA interposer card (PN 570-1181).
http://sunsolve.sun.com/handbook_pub/validateUser.do?target=Systems/J4400/components
-- richard
All disclaimers apply.
Regards Frederik
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