Staggered SpinUp

As near as I can tell, from Wiki searches and looking over a few threads over the years in this forum on this topic, UnRAID does NOT implement a staggered spinup for the drives.

(a)  Is this true?

(b)  If so, does anyone know WHY it hasn't been added as a feature?  [A simply checkbox on the Disk Settings page would let folks choose whether or not to implement it.]

©  Are there any plans to add this?    I'd think it would be an excellent feature.    Most UnRAID systems use FAR larger power supplies than they actually need just because they need to have the capacity for spinning up all the drives at once.  This feature would significantly reduce the size of the PSU's needed, and let more systems operate within the 80+ performance range of modern PSUs.

My hardware does the staggered spinup long before unRAID even starts to load.

My hardware does the staggered spinup long before unRAID even starts to load.

My hardware does the staggered spinup long before unRAID even starts to load.

Which controller?  I know the Areca supports it, but I didn't think the MV8's did.  Even with the Areca, I'd think that since you're just using it as a SATA controller, and not using the actual RAID on it, that the staggered spinup wouldn't be in effect.

Finally, once UnRAID spins down the drives, are you getting staggered spinups if you click the "Spin Up All Drives" button?  ... or start a Parity check?  ... or Stop the array?

In any event, what I'd like to see is an UnRAID-controlled staggered spinup that wasn't dependent on the specific hardware in use.

My hardware does the staggered spinup long before unRAID even starts to load.

 

My hardware does the staggered spinup long before unRAID even starts to load.

 

Which controller?  I know the Areca supports it, but I didn't think the MV8's did.  Even with the Areca, I'd think that since you're just using it as a SATA controller, and not using the actual RAID on it, that the staggered spinup wouldn't be in effect.

 

Finally, once UnRAID spins down the drives, are you getting staggered spinups if you click the "Spin Up All Drives" button?  ... or start a Parity check?  ... or Stop the array?

 

In any event, what I'd like to see is an UnRAID-controlled staggered spinup that wasn't dependent on the specific hardware in use.

 

Yes, all three of my controllers perform a staggered spinup at startup.  Also, I am using the Areca as a true RAID card...would be kind of a waste not to.

I never spin my drives down in unRAID.  It's a server...I don't care about saving power.  I tried it for a while, but with a few people accessing my Plex, and automated tools like Media Center Master, they were always staying spun up anyway.

That being said, I can see how it would be a nice feature when you click the "Spin Up All Drives" button if they were staggered.

There is a way to do a staggered spin up upon power on by using the Power Up in Standby flag from hdparm.

I've done this for years. In fact I think it's a necessary thing for unRAID since some of us build large arrays.

It's good for maintenance since you can power up a machine and one of the drives will start spinning until the controller initiates a spin up or unRAID issues the spin up.

Most motherboard controllers do not issue the spinup. the MV8's did not either.

The areca did, but only because of a RAID array and it had to check the health of the raid array.

The downside is the extra time to start unraid. Each drive is polled, a spin up occurs, once accessible, the next drive is read. This is part of the kernel. Long before the md driver or emhttp.

This could be considerable time if you have allot of drives.

In my case I did this anyway because I lost a drive once while it was starting to spin up and I shut the machine down.  It just so happened to create a bad spot on the disk and it became unreadable and unrecoverable.  I was able to save the drive using ddrescue and skipping that one bad sector. it sure did change the way I did things.

The other part of the problem is when you you press the spin up button. This will spin up all the drives at once.  What needs to happen is some sort of round robin or limit based on controller groups. I.E. some drives are set to spin up, a delay occurs, others are set to spin up, etc, etc.

This has to be done by limetech.

What we could do with a plugin is change the some disk settings or create a button on the disk page that issues the power up on standby command (or turns it off).  There are caveats to this. Some older disks do not handle power up in standby well.

I used to have a script that did this based on device serial number so I could be sure I was issuing the command to the correct device no matter where it moved in the linux device system.

Also discussed here.

http://lime-technology.com/forum/index.php?topic=2013.msg14625#msg14625

http://serverfault.com/questions/259255/hdparm-poweron-standby-is-how-dangerous

Also discussed here.

 

http://lime-technology.com/forum/index.php?topic=2013.msg14625#msg14625

 

http://serverfault.com/questions/259255/hdparm-poweron-standby-is-how-dangerous

Yes, I'd already read those threads before I posted this question.  Setting the drives to poweron in standby is somewhat a workaround ... but the problem is if you have UnRAID set to spindown the drives, as I understand it they'll all be powered on at once if you click the "Spin Up" button;  start a Parity Check; or Stop the array.    It would be SO much nicer if UnRAID implemented a sequential startup ... a simple checkbox in Disk Settings would be fine;  a delay time setting (seconds between spinups) would be a nice "tweak".

In searching through this forum and the Wiki I never found any posts by Tom r.e. this feature.  Do you know if he's ever chimed in with his thoughts on it?

In searching through this forum and the Wiki I never found any posts by Tom r.e. this feature.  Do you know if he's ever chimed in with his thoughts on it?

In searching through this forum and the Wiki I never found any posts by Tom r.e. this feature.  Do you know if he's ever chimed in with his thoughts on it?

I've never seen Tom mention it in any way.

I wonder why.  As I'm sure you know, 80+ certifications are done at 20%, 50%, and 100% loads;  and power supply efficiency drops off rapidly below the 20% load point ... often getting down to 65% or even lower when the load's below 10%.  It's not uncommon to have idle loads in the 40-50W range when drives are spun down (my Atom-based build idles at 20W;  I know of several other builds with i3's that idle in the 35-40W range; etc.) ==> and that's well below 10% of the rated capacity of the 650W and 750W units that many people use just to be sure they have ample spinup capacity.

A system with 24 drives that idles at 50W would use something in the 160-200W range at full load with all drives spinning and doing a parity check [WD Reds, for example, only use 4.4W for R/W operations ... so 24 of those would draw 106W].    A high-quality 80+ 350W PSU would be PLENTY for these systems IF the spinups were staggered ... and the PSU would be at max efficiency as low as 70W ... so it would still be reasonably efficient at 50-60W idle current; and would be running at its certified 80+% whenever a couple drives were spun up.

There seems to be another conversation about this subject matter here.

Staggered Spinup !!http://lime-technology.com/forum/index.php?topic=28064.msg248327#msg248327

Regardless of efficiency ratings etc, it's a very bad idea to rely on software settings to not blow up your PSU if all your drives decide to spin up at once for some unknown reason. All it would take is one mistake in software, and POOF, dead drives and or PSU. The power supply should be sized for peak possible draw plus a small margin.

Intentionally undersizing a PSU for a few watts (at most) of efficiency is penny wise and pound foolish in my opinion.

Staggered spinups may be desirable for other reasons, but to intentionally allow for a smaller PSU isn't one.

That is definitely food for thought Jonathan.

A system with 24 drives that idles at 50W would use something in the 160-200W range at full load with all drives spinning and doing a parity check [WD Reds, for example, only use 4.4W for R/W operations ... so 24 of those would draw 106W].    A high-quality 80+ 350W PSU would be PLENTY for these systems IF the spinups were staggered ... and the PSU would be at max efficiency as low as 70W ... so it would still be reasonably efficient at 50-60W idle current; and would be running at its certified 80+% whenever a couple drives were spun up.

That is a very good point! Could you not do staggered spinup through the RAID card?

If the controller card automatically staggered spinups, that would work very well -- there wouldn't be any concern about a situation that might cause all drives to ramp up at once.  However, as I noted in the other post where we discussed the same thing, I've basically concluded that the benefits of having sufficient capacity to handle an all-drive spinup situation probably outweigh the efficiency loss from the PSU.

  As far as a RAID controller controlling a staggered spin up goes, many, if not MOST of the older RAID controllers did stagger spin ups, on POWER ON spin up conditions.  Some RAID controllers would even be configured as masters, and slaves to insure all drives were spun up in sequence, and that multiple controllers would not spin up their drive at the same time other controllers were.  Not sure if that is even available on newer RAID cards, since I always play with newer JBOD array controllers now with unRAID.

  In the past, and still usually the case, in a true RAID environment, the drives are never spun down again, till the array is taken off line and powered down.  So a RAID controller would never do a staggered spin up anyway, exept at power up.

  The staggered spin up on the RAID controllers I have used, is also tied into the BIOS drive intitialization and discovery phase of the controller boot up process.  And I am unaware of any feature on any of the cards I have worked with allowing or providing any means of a staggered spin up of multiple drives if they are subsequently spun down after an OS is in control.

  So from a hardware point of view... I would say that IF you have controllers that do staggered spin ups of drives, AND the drives are never spun down except to power down the system... Then it should be fine to reduce the power supply size compared to a system that would be spinning up all drives simultaneously.

  In the past, drives used MUCH more power during spin-up than todays drives.  Add to that, the fact that power supplies were also much less efficient than todays power supplies.  And it can be seen why staggered drive spinups, while still a very good thing for some reasons, is not as important today as it used to be.

  I would still like to see user configurable spin-up in unRAID, but would not downsize a power supply because it was there.