Hi,

Thanks for all your input. Everyone I suspected that would be quick to respond did so :)

As I myself work with computers, I know to distrust everything I hear from "users". Unfortunately I'm not a user, but that probably doesn't make me more trustworthy :)

Tony and Rob, I *did* listen to myself, and I do have my reasons to want to do things the way I described.

First thing, the RAID isn't for safety measures. This is a workstation. The disks are RAID0, purely for performance. Everything stored is either temporary or backed up.

Frank is right, this is no card-board box. The casing is an Intel SC5000 server casing, designed to hold the 10 drives. It has enhanced cooling, with a total of 7 fans. The case reaches around 30C when running for longish periods. The drives specifications state that the drives maximum ambient temperature to meet MTBF specs are 45C. The air is sucked in from room temperature, passes the drives and exits into the cabinet (which causes the temperature to rise from the 22C it is in the room to the around 30C the air is when it exits the casing).

Also my diagnosis does not tell me that the PSU cannot sustain the power load. The PSU has been bought as what I thought was with enough headroom. It is designed to deliver 20A at 12V. The drives use 13A at 12V when they are stressed.

My diagnosis tells me that the PSU cannot quickly deliver the increase in amps that all the drives need for a very short period of time, if the demand is all drives at once. It is the going from idle to activity state that causes the problem.

There is no problem running all disks at full activity for hours from the single 550W PSU, as long as they do not all *start* seeking/reading/writing at the excact same time. There is no problem running them all at the same time (doing hefty disk access).

Frank, it isn't SCSI resets. I thought so as well, but the drives physically power off. If it was anything but power, why does it run so well with an extra PSU?

Termination, SCSI-controller, cabling, enclosure firmware has been checked. Everything flies perfectly with an extra PSU.

I do think I did my homework before asking here....


Best regards,


Lars