SATA staggered-spinup
Posted by Scott Laird Tue, 23 Oct 2007 00:06:37 GMT
Interesting trivia: staggered drive spin-up is an optional part of the SATA II spec. Unlike most SCSI drives, though, it’s not controlled through a jumper. Instead, it uses one pin on the SATA power connector. If pin 11 is floating, then the drive is supposed to wait to start spinning.
Apparently the 650W power supply in my new server only provides enough current to spin up 10 drives at once, because adding an 11th drive makes it turn off on its own immediately. Sigh. I wonder if anyone makes delayed-spin SATA power dongles?
Try to use external drives with autonomous supplies
I slave a 2nd PSU triggered by the PG line on the 1st, or sometimes a relay from the 12V or 5V line of the 1st supply.
My best success is 25 drives like this with no mods to PSUs other than a relay board plugged into the 1st drive’s molex. Beware that for proper regulation some load resistors may need to be placed across the 2nd supply o/p’s, select on test (quite high, I use 470R for most) This aides regulation when seen on a scope
gord, that sounds interesting. There’s probably room for a second PS in my case, even. But, it’d be even easier to rip pin 11 out of a couple molex-to-SATA power adapters and get delayed spin that way. I took a look at a spare that I had sitting around this morning, and it should be pretty easy. I just need to pick up a tiny little dremel head and I should be set.
The nice thing about the pin 11 trick is that it’s just a ground right now, bordering a pair of redundant grounds. So even if I get it totally wrong, nothing major should happen.
May I ask what psu you are using? I’m currently running 10 drives (9 samsung 500GB SATA and a WD 30GB IDE) on a tagan 480W without issues, and that only provides about 350W on the +12V rails.
The way staggered spin (aka power up in standby aka delayed spin) is enabled depends on the drive and the manufacturer. The WD and HGST that I have work by setting a bit in the drive’s config. You do this using a software tool such as hdparm or, at least in the case with HGST, a “Feature” tool. The Seagates that I have do not support this through software and are supposed to enable staggered spin by having pin 11 float, but when I put a really thin piece of magic tape on pin 11 to insulate it, the drive still spins up on power up.
At least with the WD drives I have with power up in standby, the JMICRON BIOS doesn’t detect the drive at boot. Once Linux 2.6.23.xx (need at least this because earlier versions libata EH do not retry IDENTIFY properly to wake the drive) boots, it finds the drive and spins them up one by one.
So, the question: what drives do you have, can you properly configure it for staggered spin, and does the supermicro AOC-SAT2-MV8 ignore disks that have been properly configured with staggered spin?