SATA Port Multipliers in FreeBSD (6.3)
cjk32 at cam.ac.uk
Fri Mar 6 05:00:18 PST 2009
Daan Vreeken wrote:
> Hi Christopher,
> On Thursday 05 March 2009 15:25:35 Christopher Key wrote:
>> I'm looking to substantially expand the storage on my FreeBSD 6.3 home
>> media server. With regards hardware, the simplest way to attach large
>> numbers of drives seem to be to use SATA port multipliers, but I've been
>> unable to find any consensus on their level of support in FreeBSD. I'm
>> currently looking at a RocketRAID 2314 and SiI3726 based port
>> multipliers. Has any had any experience with this combination?
> The Sil3726 works very well if you run a recent enough version of FreeBSD. We
> use the device in a custom storage appliance. I don't know the RocketRAID
> 2314 though. You need a SATA 2.0 controller for Port Multipliers to work.
I'm pretty sure the RocketRAID 2314 is a SATA 2.0 controller. I've
references in places to it supporting port multipliers, but have been
unable to to find any further details on quite what this means. To be
honest, I don't fully understand how the ATA system fits together.
HighPoint offer a FreeBSD driver, but I don't know whether this replaces
functionality within FreeBSD, or is an additional requirement. Nor do I
know whether port multiplier support is the responsibility of the ATA
driver, the ATA controller, both or either, nor whether the ATA
controller being a RAID card in JBOD mode affects anything. I was
thinking that for the RR2314 to work with port multipliers whilst it was
doing hardware RAID, it must fully understand how to address drives
behind a port multiplier and might do the same in JBOD mode, simply
presenting the ATA driver with a list of drives. Whether this is valid
reasoning, I've no idea.
> FreeBSD has (experimental) support for Port Multipliers since the following
> commit :
> On Thursday 10 April 2008 15:05:05 Søren Schmidt wrote:
>> sos 2008-04-10 13:05:05 UTC
>> FreeBSD src repository
>> Add experimental support for SATA Port Multipliers
>> Support is working on the Silicon Image SiI3124/3132.
>> Support is working on some AHCI chips but far from all.
>> Remember this is WIP, so test reports and (constructive) suggestions are
Thanks, I've found the relevent revision in SVN,
I'll read through the diffs to see if I can get a better idea of how
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