On 09/10/2012 12:41 PM, Jeff Siddall wrote:
> On 09/10/2012 02:52 PM, Todd And Margo Chester wrote:
>> On 09/10/2012 10:05 AM, Jeff Siddall wrote:
>>> ME software RAID1 is very reliable
>>
>> Have you had a software RAID failure? What was the alert?
>> And, what did you have to do to repair it?
>
> Never had a "software" failure.  I have had [too] many hardware
> failures, and those show up with the standard MD email alerts (example
> attached below).
>
> Jeff
>
> ----------
>
> This is an automatically generated mail message from mdadm
>
> A DegradedArray event had been detected on md device /dev/md1.
>
> Faithfully yours, etc.
>
> P.S. The /proc/mdstat file currently contains the following:
>
> Personalities : [raid1] [raid6] [raid5] [raid4]
> md3 : active raid1 sda5[0]
>        371727936 blocks [2/1] [U_]
>
> md0 : active raid1 sda1[0]
>        104320 blocks [2/1] [U_]
>
> md2 : active raid1 sda3[0]
>        2096384 blocks [2/1] [U_]
>
> md1 : active raid1 sda2[0]
>        16779776 blocks [2/1] [U_]
>
> unused devices: <none>
>

Hi Jeff,

    Thank you.

    I do not understand what I am looking at.  All four
entries are RAID1, meaning two drives in the array.
But what two drives go together?

    What does the "[U_]" stand for?  Up?  Should
md1 be [D_] for down?

    What does [2/1] stand for?

    And, just out of curiosity, is it possible to have
a hot spare with the above arrangement?

-T