AHCI and SSS

[Piergiorgio Sartor <piergiorgio.sartor@nexgo.de>]

Hi all,

I've a couple of questions about AHCI and SSS.

If I understand it correctly, SSS is used to
honor the PUS (Power Up in Standby) otherwise
known as SSU (Staggered Spin Up).
That is, if the HDDs at boot are in idle, they
will be waked up one after the other and not
all together, in order to reduce the power spike.

How about a system already running, where the
HDDs are set to idle?
For example, assuming we have a RAID-5, with
5~6 HDDs and we put them to sleep.
When the RAID is accessed, all the HDDs are
wakeup in parellel.
Is there any way to serialize all the accesses
to the HDDs?
Or, is there an other solution to the problem?

Second question.
As far as I know, only the ahci driver supports
this SSS.
How about other drivers?
How about the SAS drivers (I know, this is linux-ide,
but maybe someone will know as well)?

Thanks a lot in advance,

bye,

-- 

piergiorgio