Casper Traberg-Larsen :
So i have 2 WD HDD's in raid 1 (mirror) used for backup.
Casper Traberg-Larsen :
So.. I deleted the "missing" HDD and deactived the mirroring (raid 1) and reactivated it. It is now resyncing - but there is still this yellow triangle at disk 1?!
I would assume the yellow triangle is there because the disk is still rebuilding.
Are these WD Red drives which are intended to be used in RAID arrays? If not, you've probably run into the dreaded TLER issue.
In a nutshell, when a hard drive runs into a read error, it tries to read that sector again. It can try for almost a minute before giving up, and Windows reports a CRC mismatch. Well, the timeout before a RAID array decides a drive has died is much shorter - usually around 10 seconds. So while your drive is busy trying to re-read that sector, the RAID software says "Hmm, that drive hasn't reported back in a while. It must be dead. I'll drop it from the array."
To counteract this, there's a setting in the hard drive firmware which controls how long it should try to re-read a sector before giving up. When you use the drives with RAID, the RAID software changes this setting, and the drive always gives up trying to re-read before the RAID software drops it from the array. On WD drives, this is called TLER.
WD
deliberately removed this setting from all their drives except the Red drives, so they could force RAID users to pay more. Thus taking the I out of RAID (Redundant Array of Inexpensive Disks). If your drives are not WD Red drives, you're going to run into this problem again and again. The only fix is to replace them with WD Red drives or non-WD drives (none of the other manufacturers have pulled this stunt).
http://en.wikipedia.org/wiki/Error_recovery_control
Facebook
Twitter
Instagram