On Sun, 16 Sep 2012, Todd And Margo Chester wrote:
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
On 09/17/2012 12:22 AM, Steven J. Yellin wrote:> I believe that
this is the interpretation of /proc/mdstat:
> Consider, for example,
>
> md2 : active raid1 sda3[0]
> 2096384 blocks [2/1] [U_]
>
> The device is /dev/md2. It is raid1, meaning partitions on two disk
> drives mirror each other. One of the two is /dev/sda3; the other isn't
> given because something went wrong, but I'll guess it would be /dev/sdb3
> if sdb were working, and you would also have in the md2 line an
> identification of the second participant in the mirror, "sdb3[1]". The
> mirrored partitions have 2096384 blocks, which I think means about 2 GB.
> The "[2/1]" means there should be 2 disks in md2, but there is actually
> 1. The "[U_]" would be "[UU]" if md2 were in perfect working order, but
> the second drive in md2 is absent. Perhaps "U" stands for "up", or for
> "available" in some language other than English.
> You can have a hot spare. If the md2 line read
> md2 : active raid1 sdc3[2] sdb3[1] sda3[0]
> then the mirror would still consist of sda3 and sdb3. You can tell
> sdc3 is the spare because of its "[2]"; only [0] and [1] are needed for
> successful mirroring.
>
> Steven Yellin
>
Hi Steven,
Thank you!
It looks like in the example that all four drives are in their
own RAID1 arrays, but are missing their companion drives.
A misconfiguration perhaps?
-T
