How to disable staggered spin up?

[Koperfild]

Hi,

I've got Asus P5E-VM Do motherboard with ICH9R chipset. Is there any way I can disable staggered spin up feature or is it up to the PSU? The time needed to spin the disks up one by one becames very annoying since the quantity of disks exceeded 6.

[Adrian]

This is probably something you really don't want to do unless the power supply can in fact handle the load during start-up. I can't recall the exact terminology atm (hopefully someone with much more electrical knowledge can step in), but I think its called "Crest Factor". What it boils down to is something along the lines of, electrical devices like computers have a huge spike in terms of electrical load when they are started, way more than what it will use normally. So if you were to have a server full of drives and everything tried to start up right away, the amount of AMPs it would try to pull from the Power Supply would pretty much kill it.

 

I learned about this a long time ago when dealing with a rack of specialized servers (about 28 of them) that had to go through DC Inverters in order to connect to the data centers UPS which only supplied DC. The inverters were modular, so we had to calculate the AMP requirements of the servers to make sure we got enough to handle all the servers. We got enough where we were at like 70% load to handle failure of one of the units. I remember one big issue was to never ever turn on all the servers at the same time. Even though after the server was running in full production it only drew about 12.5 amps each, but during start-up it would spike to about 30 amps or more.

[SSD]

Hi,

I've got Asus P5E-VM Do motherboard with ICH9R chipset. Is there any way I can disable staggered spin up feature or is it up to the PSU? The time needed to spin the disks up one by one becames very annoying since the quantity of disks exceeded 6.

 

You are under a mistaken assumption that the system is staggering your drive spinup.  It is NOT.  It is more likely that a staggered spinup is the result of the system accessing first one disk, then the second disk, then the thrid disk, etc etc.  The system will wait for each disk access to complete before moving on to the next.  The net result is a staggered spinup, but not because of the PSU or any intentional power saving feature.

 

When I coded the spinup feature of myMain I set it up so that it would try to spin up to 8 drives at a time.  unRAID's spinup logic may also try to spin them up in parallel (I'm not really sure there).  But otherwise drives will spin up as they are accessed as described above.