Film-Tech Forum ARCHIVE: DSS200 Drive Bays

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Posted by Gavin Lewarne (Member # 5397) on 12-10-2014, 01:00 PM:

We have a standard DSS200. I have purchased 2 spare hard drives and was wondering if the 4 unused drive slots on the right are powered? I know they are not connected or used, but was thinking if they are not powered they would be a great way to store the spare drives for instant swap over should the need arise.

cheers

Posted by Steve Guttag (Member # 268) on 12-10-2014, 07:49 PM:

I don't believe they are powered...but you should be able to store your spare drives there all loaded up with the carriers on them for a fast swap. Given that it is a RAID 5, it shouldn't be a "rush" situation to pull the bad one and get the replacement in.

Now you could get a suitable RAID card to power up all 8 slots but I don' think that is what you are going for.

Posted by Gavin Lewarne (Member # 5397) on 12-10-2014, 08:17 PM:

thanks steve. I appreciate that with raid 5 its not an ASAP swap when one goes bad, but it just makes it easier for my other guys to swap them without having to fiddle with the carriers, screws etc if im not around.

Posted by Jason Raftery (Member # 6291) on 12-10-2014, 09:12 PM:

Actually the four unused bays are powered.

I had upgraded a site to 2TB disks and wanted to keep the original array of 500GB drives in the remaining bays on each server to have on hand in the event the new array ever lost two disks and failed. Dolby did not have a procedure to remove power from just the four extra bays, so I resorted to storing the old arrays in the projector pedestals.

Posted by Gavin Lewarne (Member # 5397) on 12-11-2014, 03:33 AM:

balls. well, I guess that puts an end to my plans. Thanks chaps

Posted by Marcel Birgelen (Member # 6801) on 12-11-2014, 03:42 AM:

As far as I know, they indeed are powered via the backplane. I'm not sure if the drives do spin up though, as they usually wait for a SATA command to do so.

Edit: I did some "fact checking" and seemingly, most disks just start to spin up once you apply the power. Some can be explicitly told not to do this, but it requires special configuration and support in both the BIOS or RAID controller and the disk.

Posted by Leo Enticknap (Member # 534) on 12-11-2014, 11:28 AM:

There is only one power connector on the hard drive controller card, so you can't disconnect the power from slots 5-8.

Posted by Mark Gulbrandsen (Member # 72) on 12-13-2014, 04:50 PM:

The extra bays are for sure not powered.

Mark

Posted by Marcel Birgelen (Member # 6801) on 12-13-2014, 08:25 PM:

How do you know that for sure? AFAIK, the DSS200 is based on the Supermicro SC835 chassis. According to their specs, there is no option to selectively disable the power to individual bays.

What's for sure is that those bays aren't connected to any controller.

Posted by Gavin Lewarne (Member # 5397) on 12-15-2014, 04:56 AM:

I guess the only thing I can do is put a drive in there and "feel" if it spins up.

p.s. Steve, I sent you a PM a few days ago but I figure you don't check for them very often.

Posted by Leo Enticknap (Member # 534) on 12-15-2014, 09:07 AM:

quote: Mark Gulbrandsen
The extra bays are for sure not powered.

The ones in one of our DSS200s certainly are, because I put drives in them, plus an eight-drive RAID card, and they're working. The green LEDs light up, the RAID card sees eight drives when it boots, and Dolby Show Manager sees 'em, too.

Posted by Carsten Kurz (Member # 5396) on 12-15-2014, 10:16 AM:

This is a RAID Backplane. They may just as well have extra logic on it to control drive spin-up. One very basic reason to have it that way is to prevent all drives + boards in a machine to draw a high inrush current at the same time. These drives MAY only spin up when the backplane tells them to, and that may only happen when there is an 8ch interface. So, without further knowledge about the backplane specs, we can not be sure.

- Carsten

Posted by Steve Guttag (Member # 268) on 12-15-2014, 02:42 PM:

Gavin, I don't use PMs so if you sent one...I never saw it, I don't get messages about it either.

That is one form of communication I choose not to use...it is just extra work.

Posted by Marco Giustini (Member # 4544) on 12-15-2014, 05:28 PM:

I may have seen two molex connectors on the 200's backplane, maybe one is for the first 4 drives and the other for the other four? Or maybe they're just linked for more current. Or maybe I'm just plain mistaken and there is just one plug. [Smile]

Posted by Marcel Birgelen (Member # 6801) on 12-15-2014, 07:56 PM:

There are two molex connectors, as one single connector would probably exceed the design specification if all drives are operating. I don't think it's a split backplane though.

Like Carsten already mentioned, the backplane contains also some limited amount of logic. Although it's essentially a pass-tru deal, there will probably be some logic for the initial spin-up of the drives, to avoid overloading the PSUs. Also, there's the logic that drives the activity and status LEDs, which are also on the back plane (the drive caddies use plastic light pipes to bring them to the front).

quote: Gavin Lewarne
I guess the only thing I can do is put a drive in there and "feel" if it spins up.

I'm curious how you're going to accomplish this [Wink]

Posted by Adam Martin (Member # 641) on 12-15-2014, 08:16 PM:

The DSS200 uses a Supermicro SAS-833TQ drive backplane. All ports are powered at all times.

Having said that, not all drives will spin up when powered. Some SATA drives support "power up in standby" mode and will not spin up until told to do so by the SATA controller. HGST/Hitachi notes in their troubleshooting tips that their drives will not spin up without the SATA data cable connected.

In a standard recent version of Dolby software, the 3ware [9650SE-4LPML] RAID controller is set to utilize staggered spin up for drives that support it. Once the RAID controller initializes, it delays for 2 seconds and then spins up the first drive. Subsequent drives are spun up with 1 second delays in between. This is used to control the surge of power used when booting.

I say "standard recent version" in that the RAID configuration was recently (end of 2012) updated so that the weekly RAID verification did not occur during Friday night's prime set. A 6:00pm Friday start time makes sense for a business server, but not a cinema server. Other items in the RAID configuration may have also been updated at that time.

So, the short answer to the OP's question is "it depends". Personally, I wouldn't store backup drives in the unused drive slots. At least, not plugged in all the way so that they are mounted in the backplane connectors and receiving power, spun up or not.

Posted by Marcel Birgelen (Member # 6801) on 12-16-2014, 02:37 AM:

I've tried it with a Seagate ST3000NM0033 (3TB "enterprise" drive), this one happily spins up once you just connect the SATA power. I've just tried it with a WD Green WD20EARX (2TB "Green" desktop drive), this one doesn't seem to spin up with just SATA power connected, at least I cannot feel or hear it spinning up.

So, it indeed really depends on drive and maybe even on the firmware you're running on it.

The problem with not putting the drives in the whole way is that you most likely will not be able to put the front bezel on. Also, you could have co-workers which think this is a configuration error and put them back in. If this does not apply to you and you can happily live without the front bezel/cover then it might be just fine.

P.S.: You do not want to use those "Green" drives in your RAID.

Posted by Gavin Lewarne (Member # 5397) on 12-16-2014, 04:48 AM:

I was lucky enough to find 2 identical hitachi drives, right down to the firmware version to those currently installed in it from the factory on Amazon.

Ill connect one to the spare sata power on my PC and see if it spins up.

Posted by Carsten Kurz (Member # 5396) on 12-16-2014, 06:09 AM:

This is the backplane manual.

http://www.supermicro.com/manuals/other/CSE-SAS-833TQ.pdf

- Carsten

Posted by Marcel Birgelen (Member # 6801) on 12-16-2014, 10:22 AM:

I've quickly scanned the manual, but I didn't find anything to regulate the power per port. There are a few jumpers, but those seem to control the fans, not the ports.