[CentOS] Odd behavior of a CentOS 7 box after repair of an external RAID

[m.roth at 5-cent.us]

Valeri Galtsev wrote:
>
> On Fri, March 25, 2016 9:55 am, m.roth at 5-cent.us wrote:
>> 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,
>
> You did unmount filesystem on the machine before that, right?

Of course!
>
>> 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.
>
> 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

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).
>
> (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 ;-)

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