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ChrisA

macrumors G5
Jan 5, 2006
12,578
1,694
Redondo Beach, California
I use WD Red 3TB drives in my RAID5 array - never had any issues whatsoever. Highly recommended.

If you own only one raid array then you don't have a large enough sample to have good statistics. You need to look at hndereds of arrays.

You just have to decide what kind of failure you can live with. Canyou wait while an array rebuilds? Can you risk having no redundancy after one failure? Many people will decide they need two parity drives (raid 6) to they still have redundant drive after a failure. Others will decide they need two arrays and keep them sync'd. Other will want three arrays that are geographically dispersed and kept sync'd.

And you STILL need to find a way to back this all up.
 

cwright

macrumors 6502a
Original poster
Jan 5, 2004
573
0
Missouri
Hate to revive this thread, but I'm having lots of trouble with my RAID setup and customer support seems to have stopped trying to help. Maybe you guys will be able to?

Long story short - bought the Areca 1882x card and 8-bay tower, setup RAID 5 with Western Digital Red drives. It worked fine until a few months ago when I started finding corrupt data on the drive, even though at the time there was no sign of any failed drives. I sent the RAID card in to make sure it wasn't failing - no problems there. Got it back, made sure everything was backed up. Now the RAID Manager says Slot #6 has failed, but none of the lights on the tower indicate that that drive has failed - or any of them, for that matter. Instead, when I copy to the RAID volume now, I see blinking activity lights on all drives except the second one from the top. Wouldn't that be #2, not #6?

To make absolutely sure I'd get the correct drive to send in for replacement, I deleted the RAID, and took all eight drives out and inserted them one by one into my Mac Pro and formatted each of them. This worked on all of them without any errors - I did not find a failed drive. So I put them back into my tower and setup a new RAID 5 volume. I copied all ~12TB of data back onto it overnight with no issues and everything worked fine for a couple days before I started getting the same error - a degraded RAID volume with drive #6 failed. And once again it is the 2nd drive from the top that doesn't flash an activity light when transferring data.

The kicker is when I put all of the drives back into the RAID tower I'm not even sure that I put them back into the same slots.

Here's what my RAID Manager looks like:
RAIDManager.png


And here's a video showing what the indicator lights look like while copying to the drive: Link

I'm starting to think this could be a problem with the enclosure - but any other suggestions would be greatly appreciated!
 

wonderspark

macrumors 68040
Feb 4, 2010
3,048
102
Oregon
Ok, here's the deal:

- Slots 1-4 and 5-8 are stacked backwards most likely because you have the two mini-SAS cables backwards. If you swap them, you will then have 1-4 on the top, and 5-8 on the bottom of the stack of eight. Then Slot 6 will be sixth from the top. I have my cables labeled to prevent this confusion. :)

- The drive in "slot 6" is bad (or going bad), and needs replaced. Go online to Western Digital, enter the serial number in the website, and get an RMA for replacement. Swap in the new one, and you're back in business. It should be under warranty still, so it will be free.

- Click on the drive in slot 6 and make note of the physical HDD serial number. You can rebuild the RAID after moving the drive in the slot with no activity to another slot, and you should see the fault move to the newly relocated slot. That will eliminate the possibility that the slot, and not the HDD, is bad. On the other hand, if the HDD in the same slot is bad, and you see it's not that same HDD serial you took note of, then you know it *is* the slot, not the HDD.

- Lastly, I recommend RAID 6 instead of RAID 5. With the 1882, you should still get excellent speeds. I have the older 1880ix-12, and see 715-817MB/sec read/writes with an 8-bay tower using WD RE-4 HDDs.
 
Last edited:

cwright

macrumors 6502a
Original poster
Jan 5, 2004
573
0
Missouri
Ok, here's the deal:

- Slots 1-4 and 5-8 are stacked backwards most likely because you have the two mini-SAS cables backwards. If you swap them, you will then have 1-4 on the top, and 5-8 on the bottom of the stack of eight. Then Slot 6 will be sixth from the top. I have my cables labeled to prevent this confusion. :)

- The drive in "slot 6" is bad (or going bad), and needs replaced. Go online to Western Digital, enter the serial number in the website, and get an RMA for replacement. Swap in the new one, and you're back in business. It should be under warranty still, so it will be free.

- Click on the drive in slot 6 and make note of the physical HDD serial number. You can rebuild the RAID after moving the drive in the slot with no activity to another slot, and you should see the fault move to the newly relocated slot. That will eliminate the possibility that the slot, and not the HDD, is bad. On the other hand, if the HDD in the same slot is bad, and you see it's not that same HDD serial you took note of, then you know it *is* the slot, not the HDD.

- Lastly, I recommend RAID 6 instead of RAID 5. With the 1882, you should still get excellent speeds. I have the older 1880ix-12, and see 715-817MB/sec read/writes with an 8-bay tower using WD RE-4 HDDs.

Thanks so much for the help. I think it's safe to safe I never would have guessed the mini-SAS cables were switched, but that has to be it. Glad it's likely to be a simple solution! My week is swamped but I will take your advice this weekend for identifying the problem drive, and I will definitely build a RAID 6 once I get it sorted out.
 

wonderspark

macrumors 68040
Feb 4, 2010
3,048
102
Oregon
Thanks so much for the help. I think it's safe to safe I never would have guessed the mini-SAS cables were switched, but that has to be it. Glad it's likely to be a simple solution! My week is swamped but I will take your advice this weekend for identifying the problem drive, and I will definitely build a RAID 6 once I get it sorted out.
No prob.

I meant crossed, not swapped, but you probably know that. Only swap the ports on the RAID box. :p

I like RAID 6 because if you pull the wrong drive, you still have one more to go without losing data, and if you don't have another drive handy just yet, you can breathe a bit easier until the replacement arrives.
 
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