Good Morning,

We have a dell power edge 6850 with a degraded drive in the RAID array.

I have never had to recover such an issue, so any help or advice would be welcome.

Basically it hasn't affected the server at an operating system level, but has slowed down performance, I have a replacement drive in hand but as this is our main database server I want to proceed with extreme caution.

My options as I see them are -

  1. Can I just hot swap the degraded drive with the new one and the data will automatically re-sync and we are all back to normal presumably this is dependant on the current raid configuration?

  2. reading various comments on-line I may need to re-configure the RAID array and re-build the broken drive? This screams disaster to me with the main worry being that I wipe any other data.

Option 1 would of course make my day.

Thanks in advance


You had never a degraded raid? Strange. The first thing you should try is to pull out the "broken" drive and put it back in again. Sometimes the drives just get thrown out but have no defect.

If this works the drive will blink green and start to rebuild at once. If it fails the drive will blink orange again - then the drive is really faulty.

If the drive is faulty you can replace it with a new one. If you did not fiddle with the RAID-controllers default settings, it will rebuild automatically. (PERC4i?)

  • I'm going to disagree with you here. If a RAID controller calls a disk dead, I'm inclined to believe it. Because the RAID controller called it dead, my maintenance contract will allow me to get a new one. Better to be safe than sorry and get a new disk, in my opinion. – Ben Pilbrow Aug 18 '11 at 21:08
  • Matt is talking about a Dell PE6850 here (apparently without hardware support). Ive got about every second week a degraded raid in one of "my" Dell PEs. With my first cases I called the support. First action: please pull out the disk, wait a few seconds, put it in again. If the error persists call again. From my experience now I can say that 50% of these disks recover after being put back in. I asked Dell why this happens. Answer: Its a timing thing betwenn raid controller and disk. – Nils Aug 21 '11 at 19:21
  • @BenPilbrow this is a known issue with older Dell PERC's they fall out of sync and go degraded when there is nothing actually wrong with the drive, hence the pop it out and put it back in first step. – Zypher Jun 27 '12 at 21:31

Option 1 is what should happen. If you dont see it happening, you might have to set the new drive as hotspare - then it will definitely start to rebuild. Make sure the rebuild happens (at least mostly) OOH, and that you have a working backup just in case.

Managing and monitoring disk states is easiest with OMSA

  • Thanks, the current raid configuration is RAID 5 so I am hoping from what I have read that option 1 will be the case! – Matt Sep 30 '10 at 9:03
  • one further question if I may, the reaplcement drive I have is a 15K and the others are 10K in speed. – Matt Oct 1 '10 at 7:53
  • will this still work as normal or will performance be reduced on the other drives? – Matt Oct 1 '10 at 8:03
  • it will work, although with the speed of the slowest drive of course – dyasny Oct 2 '10 at 14:10

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