Odd Behavior Of A CentOS 7 Box After Repair Of An External RAID

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I don’t think I’ve seen this with CentOS 6 or 5, but I had to repair an external RAID box this morning. The server, running CentOS 7, has an LSI
HBA card in it, and it’s presented to the system as /dev/sdb. I shut off the RAID controller, powered it off, did the repair, then plugged everything back in (that includes the two fiber cables and the ethernet), and brought the RAID back up. I even used its web page to restart the controller (in the RAID box.

I couldn’t remount the drive until I rebooted the server.

I tried scsi-rescan-bus, and nothing. In the logs, I saw it try to mount it, then unmount it, and complain that the drive wasn’t active.

I was expecting it to act like a hot-swap device. Any clues as to why, rather than see it removed, it continued to see it as “inactive”?

mark

4 thoughts on - Odd Behavior Of A CentOS 7 Box After Repair Of An External RAID

  • You did unmount filesystem on the machine before that, right?

    Before powering off/disconnecting RAID box, did you remove resembling SCSI
    device? this is done if my memory doesn’t fail me by doing this:

    echo 1 > /sys/class/scsi_device/6:0:0:0/device/delete

    (replace “6:0:0:0” with your device’s address). If you didn’t remove the device before powering it off, I’m not surprised. If you did remove the device before powering it off, I’m puzzled ;-)

    Valeri

    ++++++++++++++++++++++++++++++++++++++++
    Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247
    ++++++++++++++++++++++++++++++++++++++++

  • Valeri Galtsev wrote:

    Of course!

    No – I’ve never done that. With hot-swap drive bays, the system sees it going out, and says so, and then the drive goes away, or becomes inactive… but when I shove one back in, it sees it, though it may make it as /dev/sd[letter+1] (that is, if it had been /dev/sdb, it’s now
    /dev/sdc).

    As I said, I expected the scsi-rescan-bus to clear it up, but though it saw it, nothing changed.

    mark

  • Then we will need real expert to chime in on this…

    Did you do scsi-rescan-bus after you disconnected the device, and then again after you connected it back? I’m just shooting in a dark, but the first one probably will remove the device that disappeared, and the second will add the device back. And it may do nothing about devices that exist on the bus, even though they disappeared temporarily, then re-appeared. I, simple person, knowing not all devices/scsi controllers support hot swap, would just remove the device as I said in previous post before disconnecting (an rescan scsi bus after connecting it back).

    Valeri

    ++++++++++++++++++++++++++++++++++++++++
    Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247
    ++++++++++++++++++++++++++++++++++++++++

  • Valeri Galtsev wrote:

    Yeah, I was wondering about, what, dbus? dracut?

    No. I didn’t think of doing that, because I thought that once I’d shut the RAID controller down, and powered it off, the system would have noticed.

    That might have worked; certainly, it’s a thought to keep in mind for the future (he says, pushing it onto the stack).

    mark

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