2 Volume in single EX4

My Cloud OS 3 Personal & Network Attached Storage My Cloud EX4
1

Hi All,

I would like to clarify the RAID setup in My Cloud EX4.

All the 4 slot is occupied with 2TB hard drive. From the RAID profile I can see the following:

Volume_1 | RAID 1
Volume_2 | RAID 1

  1. Does that mean Volume_1 = Slot 1 and Slot 2, and Volume_2 = Slot 3 and Slot 4?

  2. Is Volume_2 mirrored of Volume_1? Which mean I cannot take out the hard drive on Slot 3 and Slot 4?

Thanks,
CL

2

As far as which volumes are which drives, it depends on how you configured it. But I can tell you that volume 2 is NOT a mirror of 1.

3

Hi,

  1. The RAID was setup many years back, I don’t have the info of which drive goes to which Volume. Is there any way to check on this?

  2. Currently my Drive 2 is now in “Bad” state, and my Volume_1 is in “Degraded” state, so I assume Drive 1+2 = Volume_1? And Drive 3 + 4 = Volume_2? And from what I understand is totally 2 separate Volume, not related?

  3. All my files are created under Volume_1, I don’t have files in Volume_2. I plan to replace the faulty Drive 2 with one of the Drive in Volume_2 (Drive 3/4). Which is why the initial question posted whether Volume_2 is actually the mirrored of Voume_1. (Western Digital Engineer told me IT IS, and advised me NOT TO format the Volume_2. Else it break the RAID 1 mirror)

  4. I intend to Format my Volume_2 through Setting>Utilities and use one of the Drive in Volume_2 to swap out the faulty Drive 2. Will there be any concern of this action?

Thanks in advanced!

4

Log in via ssh and post the output of the commands

cat /proc/mdstat

And

mount

5

Hi,

Output:

cat /proc/mdstat

Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md2 : active raid1 sdc2[0] sdd2[1]
1949319032 blocks super 1.0 [2/2] [UU]
bitmap: 0/1 pages [0KB], 131072KB chunk

md1 : active raid1 sdb21 sda2[0]
1949319032 blocks super 1.0 [2/1] [U_]
bitmap: 1/1 pages [32KB], 131072KB chunk

md0 : active raid1 sdd1[3] sdc1[2] sdb14 sda1[0]
2097088 blocks [4/3] [U_UU]
bitmap: 8/16 pages [256KB], 8KB chunk

unused devices:

mount

%root% on / type unknown (rw)
proc on /proc type proc (rw)
/dev/ram0 on / type ext2 (rw)
sysfs on /sys type sysfs (defaults)
mdev on /dev type tmpfs (defaults)
proc on /proc type proc (0)
cgroup_root on /cgroup type tmpfs (rw,nosuid,nodev,noexec)
memory on /cgroup/memory type cgroup (memory,rw,nosuid,nodev,noexec)
ubi0:config on /usr/local/config type ubifs (0)
squash on /usr/local/tmp type ramfs (rw,size=105m)
/usr/local/tmp/image.cfs on /usr/local/modules type squashfs (rw,loop=/dev/loop0 )
tmpfs on /mnt type tmpfs (size=1m,nr_inodes=0)
tmpfs on /var/log type tmpfs (size=40m,nr_inodes=0)
tmpfs on /tmp type tmpfs (size=100m,nr_inodes=20000)
none on /proc/bus/usb type usbfs (rw)
/dev/sda4 on /mnt/HD_a4 type ext4 (rw,noatime,nodiratime,usrquota,grpquota)
/dev/sdb4 on /mnt/HD_b4 type ext4 (rw,noatime,nodiratime,usrquota,grpquota)
/dev/sdc4 on /mnt/HD_c4 type ext4 (rw,noatime,nodiratime,usrquota,grpquota)
/dev/sdd4 on /mnt/HD_d4 type ext4 (rw,noatime,nodiratime,usrquota,grpquota)
/dev/md1 on /mnt/HD/HD_a2 type ext4 (rw,noatime,nodiratime,usrquota,grpquota)
/dev/md2 on /mnt/HD/HD_b2 type ext4 (rw,noatime,nodiratime,usrquota,grpquota)

6

Ok, that indicates that group “md1” is indeed made up of drives 1 & 2, and “md2” is made of drives 3 & 4.

Further, it shows that group “md1” is mounted as “/mnt/HD/HD_a2” and “md2” is mounted as …“b2.”

So now to confirm that Volume 1 is which one, from the SSH login, do

cd /shares/Volume_1

if yours changes the prompt to something like this:

root@WDMyCloudEX4 HD_a2#

… that confirms that a2 (and thus md1) is indeed Volume 1.

7

Hi,

Thanks for the info, appreciate it.

I swap Drive 3 with Drive 2, and run a manual rebuild. But I notice the RAID 1 of Volume_1 doesn’t rebuild based on Drive 1+2. It seems Volume_1 follow the Faulty Drive (which is under Slot 3 now).

The Volume_1 now is consisting Drive 1 + 3. Am I reading this correctly? Is there anyway I can rebuilt Volume_1 with a Volume_2 Drive?

cat /proc/mdstat

Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md2 : active raid1 sdb2[0] sdd2[1]
1949319032 blocks super 1.0 [2/2] [UU]
bitmap: 0/1 pages [0KB], 131072KB chunk

md1 : active raid1 sda2[0] sdc2[1]
1949319032 blocks super 1.0 [2/2] [UU]
bitmap: 0/1 pages [0KB], 131072KB chunk

md0 : active raid1 sdd1[3] sdc1[2] sdb1[1] sda1[0]
2097088 blocks [4/4] [UUUU]
bitmap: 0/16 pages [0KB], 8KB chunk