you psu must be dimensioned to work with everythink at full work load (it´s a real production NAS right?! not a test) your SAS/IDE/SATA controller and HDD manual should be checked how hdd wake up? one command (read/write) over sata/sas/ide channel wake it up? on linux raid we have a read algorithm and a write algorithm if a raid1 write occur all disks will wake up if a raid1 (raid0 or another) read occur only the disk will wake up but check you SATA/IDE/SATA controller, how it wake up your disk, and how you hdd wake up 2011/1/31 Piergiorgio Sartor <piergiorgio.sartor@xxxxxxxx>: > Hi all, > > assuming there is a NAS, with, for example, 10 HDDs > in RAID-6. Assuming the HDDs are put in standby, in > order to save energy, when the NAS is not used. > How is the spin up sequence when the corresponding > /dev/mdX device is accessed? > Will the system spin up one HDD at time or all together? > > Obviously, one at time will limit the peak current, > thus allowing a better dimensioned PSU, working almost > always around the optimal efficiency point. > > Thanks a lot for any information on the topic, > > bye, > > -- > > piergiorgio > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Roberto Spadim Spadim Technology / SPAEmpresarial -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
