[CentOS] Bare drive RAID question, was RE: *very* ugly mdadm issue [Solved, badly]

[SilverTip257]

On Fri, Sep 5, 2014 at 4:05 PM, <m.roth at 5-cent.us> wrote:

>
> > That's why I like the [block] device naming strictly derived from
> topology
> > of machine (e.g. FreeBSD does it that way), then you know, which physical
> > drive (or other block device, e.g. attached hardware RAID) a device
> > /dev/da[x] is. I remember hassle when Linux switched numbering of network
>
> How? I've had them move around on a non-RAID m/b (for example, a drive
> fails, and you put one in an unused bay, and then you've got, say, sda,
> sdc and sdd, no sdb, until reboot), and even then, it's *still* a guessing
> game as to whether hot-swap bay upper left, lower left, upper right lower
> right are sda, sdb, sdc, sdd, or sda, sdc, sdb, sdd, or, for the fun one,
> lower right is sda....
>
>
Removing the device from the SCSI subsystem helps alleviate this problem.

By "logically" removing the failed device, you free up /dev/sdb (that just
failed) to then use that again for the replacement drive.  In all my cases
the new drive goes in the same slot and through experience the new drive's
device name has been the same as what I removed.

There are RH docs on the commands for removing/adding from the SCSI
subsystem.
Matter of fact, I posted links to the RH docs on this topic a little while
back.

[0]
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/5/html/Online_Storage_Reconfiguration_Guide/removing_devices.html

-- 
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Mike
//  SilverTip257  //