Have you considered a power problem with those 2 drives? Not power management - 12v power for any 3.5" drives or (much more likely) 5v power to any 2.5" drives.
This is less likely when drives have their own power supply (external drives), more likely if they are in a powered rack, and much more likely if they get power from the motherboard.
You could check the connections, change the cables, and/or switch the ports to test.
It definitely could be a power issue...from a hardware standpoint. That's usually been a sign of a dying PSU or drives that they drop off.
Well, unless my 700w single rail psu is too weak to drive this server,which i think not,as it can deliver 56amps, it isnt the power, also,i have changed connectors,cables and drive slots so many times to no avail. The PSU is brand new btw,and if power was an issue,shouldnt the power led´s on my drive cages go out also, if the drive was shutdown due to power?
I am almost 100% certain it is a conflict between windows power management and flexraid and/or the smart monitoring functions/programs i use, as the problem seem to have gone if power management is shut off when updating/validating my flexraid.
*UPDATE*
OK, so i tried to run a flexraid verify last night and ofcourse 12 hours in to the damn thing with 10% left to go, drive 15 again disappeared and flexraid crapped out with error,so i shutdown the server for the night, and this morning the box boots to black screen of death. I have to boot safe mode to get windows to appear.
I am getting really tired of this crap not working as intended, and i am running out of ideas of what this could be. Unfortunatly i do not have a different psu to try and change that,and i cant afford one for some time.
I am gonna re-install windows to try and see if this is the problem,i doubt it,but like i said,i am running out of ideas
How are your HDDs receiving power? Depending on how the power is being delivered, the HDDs may be getting a voltage drop at the drive that may be causing them to cut out, especially if the power is going through small cables, multiple splitters, connectors (even gold plated connectors can develop a high enough resistance to be problematic), and/or long cables, all of which increase resistance in the cables. At the voltages used, it doesn't take much resistance to cause a significant voltage drop, the 5v feed probably being the most sensitive to voltage drop. With 20 HDDs, the current draw could easily exceed 12A total. My Corsair PSU uses #18 cables, which is larger than most PSUs, and the SATA power cables have only four sockets on them. Most splitters and extensions I've seen are only #22-#26.
My case has room for only seven HDDs (six permanently installed and two hot swap bays) and an SDD. Still, I made up a single cable to feed the SDD and the six permanently installed HDDs. I kept it as short as possible and used #14 wire to avoid as much voltage drop as possible (appearance was a minor consideration). Each of the two swap bays has its own feed from the PSU since I read in a review that if they were on the same feed as the other drives, inserting a HDD would cause a voltage dip that would cause the other drives to drop out (I also used #14 for those cables but mostly because I already had a 100' spool of the stuff). I'm also using an HX750 to make sure the 5v rail was adequate even though only for just 8 drives.
Then again, it might be something else (such as the OS needs reinstalling) and I'm full of beans.
Out of curiosity, how are the HDDs connected to your OS? Are they in RAID groups? There are only so many drive letters available. Pictures of your setup would be nice (I'm also curious to see how you crammed all the HDD cages in a case designed for "only" 12 HDDs; it has to be pretty clever).
Since my psu is a single rail psu (recommended by unraid), my drive cages are all fed from 1 cable,with a 1sata -> 2molex converter,and each drive cage needs 2 molex to power 5 drives,i have no idea of the gauge of the wires,but like i mentioned this psu is rated for 52 amps, more than enough to power the 20 drives, which at max need 1,72amps on spinup,if it was the psu,wouldnt the power light on the drive cage also turn off when the drive was turned off?
I do not use hardware raid,i use flexraid (software solution) and each drive has its own drive letter, which is also why i flashed my sata controller to IT Mode,so it will act like a "dumb" sata passthrough controller instead of raid or jbod.
How i "crammed" 20 drives into this cage,simple enough, gut it,flatten 5.1/4inch drive tabs,insert 4x 5in1 drive cages,and voila 20 drive spots, with a ssd drive spot in bottom of case. This case is made for this,which is why it is so customizable, see image
Ok, that is clever how you got all those drives in there. One concern that comes to mind is how cool are they running? It doesn't look there is much room for air to flow across them.
Just because the PSU has a single rail doesn't mean each socket can support the full amperage available. Per regulations, PSU cables are limited to no more than 20A each (many PSUs limit theirs to only 16A but methinks Corsair rate their sockets at 20A). You potentially can be drawing as much as 35A during spin-up (if you aren't set up for staggered spin-up) although that probably hasn't happened since the over current circuitry in the PSU would have cut the power to all drives. The HDD light doesn't really tell you much about the voltage going to the drive so the fact it stays on isn't really relevant here.
Based on what you have told me here, your drives are probably starving for juice and/or, possibly, are overheating. Even if you aren't exceeding the ampacity of your cables (a quick and dirty check would be to feel the wires while they are in operation to see if they are warm or not; they shouldn't be), you can still have enough voltage drop due to resistance to hamper the operation of your drives. The easiest (and cheapest) thing you can try would be to spread the load to more than one cable. You have two SATA power cables and two molex cables on that PSU and the wires on the PSU cables are #18 (that's good news, at least). If you aren't using the molex cables to power your case fans (which you probably are since Antec fans usually have a feed through four pin Molex connector instead of a more conventional three or four pin fan connector), you could run each cage of drives on a single cable. Although the resistance per cable set wouldn't change (unless you up the size of the wires on any extension cables), cutting the current flowing through each cable will reduce the voltage drop. Even running two cages on each PSU SATA power cable will be better than running all four off one cable.
Hmm,never thought about that. Gonna try that as soon as windows have re-installed. One thing though, why is it ALWAYS the same drives dropping out? And why does it only happen when the drives are active?
There are fans on each of the drive cages, i replaced the orginal ones for ones that are low noise which have also been recommend for this use on unraid forums, no drive EVER exceeds 43degrees centigrade at present time,and new studies actually show drives perform much better when running a little hot,i just read an article about it not 2 weeks ago,so it is DEFINITLY not a heat problem,also,i run the case with no side cover on,which also helps with airflow.
This is v2 of the ones i use, http://www.xcase.co.uk/product-p/caddy-53v2.htm i use v1,which is actually norco cages,rebranded to x-case. I know there has been some problems regarding the sata connectors on the backplanes of these cages, but i have exchanged these exactly for that reason.
*UPDATE*
OK,so now each drive cage is on its power own cable, with the first drive cage sharing power cable molex with the case top fan and back fan
Last edited by Tsunamijhoe; 21 Jan 2013 at 11:43.
Oh, wow! Not only did you have 20 HDDs on one cable but there also was four fans (one per cage) on it. I'm surprised any of the drives worked.
Not every HDD is going to have the same tolerances to low voltage so that may explain why the same ones have been dropping out.
Although I would prefer to keep them a bit cooler, 43°C max is a comfortable temperature to keep them at so I agree, heat isn't a problem.
Now that you have split up the power feeds, it's hurry up and wait to see if it helped. If not, I have another idea that won't cost anything but time to check.
Hehe,actually i never thought about having all power consumers on 1 cable could be a potential risk for shutdowns or worse, which i why i love these forums,i learn something every time.
I am running a flexraid verify tonight,which is extremely hdd intensive,and will take about 12-14hrs,it if completes with no hiccups we might have solved the problem.
I am apprehensive though, as one boot up had 1 drive not mounted,but that could be due to windows not having installed the drivers correctly,as every bootup since all drives has been online,and all drives are reported by my sata controllers as present.
I will let you know sometime tomorrow if all goes well,and thank you so much for your help
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