Re: [opensuse] 10.2 no RAID to 11.0 RAID 1


----- Original Message -----
From: "Andrew Joakimsen" <joakimsen@xxxxxxxxx>
To: "Brian K. White" <brian@xxxxxxxxx>
Cc: <opensuse@xxxxxxxxxxxx>
Sent: Monday, September 22, 2008 4:05 PM
Subject: Re: [opensuse] 10.2 no RAID to 11.0 RAID 1


On Mon, Sep 22, 2008 at 3:27 PM, Brian K. White <brian@xxxxxxxxx> wrote:

It's perfectly possible to force a rebuild.
In fact, you can force rebuilds in mdadm in situations where no firmware raid will ever let you.
If you don't know how, that's a you problem not an mdadm problem.

I know how and issue the right command. It say /dev/sdb3 or whatnot
DOES NOT EXSIST.

But if you do ll /dev/sdb3 or even cat /dev/sdb3 the device is obviously there.

So yes mdadm is crap and should never be used. If you need to do mdadm
/dev/md0 --fail /dev/sdb3 and it say sdb3 do not exist there is a
serious issues of the developers piping their toilets into their code.

Wrong. (Unless you can supply enough exact commands and responses and other observations to prove your diagnostic process and deductions aren't full of holes. You have not done so above.)

I have seen a few different things that each were different problems, yet each could have been described roughly as above, and yet in each case the drive was not actually unavailable and all desired operations were able to be performed somehow. The exact steps varied in each case because the exact problem varied in each case. I don't know which of the exact problems you actually had, because as I said, there was just in my own little experience more than one way to get something roughly like that, so I can't say what exactly you could or should have done that would have worked.

This all assumes good hardware btw. A buggy disk or controller could actually make a disk appear bad and then later good again or good then lock up etc..
As far as I'm concerned, you could have bad hardware even. You are saying something doesn't work, but you are not showing your deductive process and so the claim is meaningless. Send me your problem disks that you think are impossible to assemble and I bet in a little while I can tell you how to assemble the array as long as there actually is enough there to use. (if you did something stupid and blew away metadata that can't be recreated or inferred, well no hardware raid card will save you from that either.)

And I'm not even slightly an mdadm guru. I simply spent a good solid weekend and then several smaller incidents experimenting. I would say it's still black art to me. But even at this level I already have actually performed actions you claim are impossible, and have seen symptoms like you decribe above, except I looked at the problem longer than 13 seconds and discovered the problem was not as it seemed and that it was prfectly solvable in every case so far. That includes those 10 boxes I was talking about. The disks kept failing randomly, but it was always possible to rebuild and rejoin them. It sometimes took some poking and insight. I'm not saying it was always obvious what to do or why. Just that it always turned out to be do-able even when it looked impossible based on the first and most obvious commands.

So far my assertion stands. You should not expect mdraid to work for you, but that has no bearing on other people or on mdraid itself.
You are merely saying that because you don't know how to fly helicopters, that helicopters are garbage.

I wish any of my machines had any problem right now so I coud show exact commands myself, but they don't. Including all those impossible mdraid boxes.

Brian K. White brian@xxxxxxxxx http://www.myspace.com/KEYofR
+++++[>+++[>+++++>+++++++<<-]<-]>>+.>.+++++.+++++++.-.[>+<---]>++.
filePro BBx Linux SCO FreeBSD #callahans Satriani Filk!

--
To unsubscribe, e-mail: opensuse+unsubscribe@xxxxxxxxxxxx
For additional commands, e-mail: opensuse+help@xxxxxxxxxxxx

Relevant Pages

  • Re: [opensuse] 10.2 no RAID to 11.0 RAID 1
    ... 10.2 no RAID to 11.0 RAID 1 ... you can force rebuilds in mdadm in situations where no firmware raid will ever let you. ... Send me your problem disks that you think are impossible to assemble and I bet in a little while I can tell you how to assemble the array as long as there actually is enough there to use. ... One thing I've seen, which I don't think is your problem but shows the kind of thing that happens, a disk will drop out of the array and reappear instantly as a higher drive letter than the system really has. ...
    (SuSE)
  • HELP Recover software RAID5...
    ... I am hoping some brilliant sysadm can help me recover my software raid 5. ... Over Time as the media drive was filled up, I add additional drives to the ... mdadm: /dev/sdh1 requires wrong number of drives. ... mdadm: /dev/sdh has wrong uuid. ...
    (comp.os.linux.misc)
  • Re: Mdadm -- Restoring an array
    ... past, when I've tried to restore a RAID, I've had trouble with it. ... The man page for mdadm makes it look like a RAID can be reassembled ... to tell mdadm to scan local drives and re-assemble an existing RAID. ... Of course, if a drive is replaced, you'll need to create a new conf file. ...
    (Debian-User)
  • Re: Help: F11 anaconda doesnt see my hard drives
    ... When you say softraid, you mean linux software raid, rather than bios raid or hardware raid? ... Something in Anaconda is failing to see the second and the third drive on a machine with the first drive being an IDE drive, and the 2nd and the 3rd drive being SCSI drives. ... It doesn't see the drives, but I can flip over to the ALT-F2 shell, and run mdadm --assemble --scan. ... This sounds as if either the raid or scsi modules are not being loaded. ...
    (Fedora)
  • Re: RAID 0+1 (Problem)
    ... I followed the steps in the link below but my RAID 10 array had a problem ... But after a reboot, I got errors re this new RAID device ... mdadm: ... And definitely talk to your boss about WHY he wants mirrored stripes. ...
    (Fedora)