Building Out XenServer 6.5 with USB Boot and Software RAID 10

scottalanmiller

Using RAID 10 in names anywhere is very confusing and hard to read. I think several of these issues are partially stemming just from poor naming conventions. Name mount points by purpose, not technology.

Romo

You can't mount /dev/md0, because according to the mdadm --examine --scan ouput, the array, is at /dev/md/0

StrongBad

@Romo said:

You can't mount /dev/md0, because according to the mdadm --examine --scan ouput, the array, is at /dev/md/0

Good eye, that was hard to see.

Romo

What is the ouput for:
cat /dev/md/md-device-map

DustinB3403

cat /dev/md/md-device-map
cat: /dev/md/md-device-map: No such file or directory

Romo

@DustinB3403
ls /dev/ | grep md

DustinB3403

Romo

@DustinB3403 can you please show us the output of your mdadm.conf file, last time I believe it was cut off because the UUID's dont show.

DustinB3403

@Romo

There is now a new record (3rd line)

Reid Cooper

That can't be right. I'm sure only one of those lines is supposed to be there.

Romo

Quite strange that the first two entries don't have a UUID set, mdadm needs the UUID set.

We could try to manually edit the file, adding the UUID from the last entry into the first entry, and then removing entries 2 and 3.

DustinB3403

@Romo Like so?

[root@eaglexen-baby mnt]# cat /etc/mdadm.conf 
ARRAY /dev/md0 level=raid10 num-devices=4 metadata=1.2 name=eaglexen-baby:0 UUID=5bd9375b:2166352e:622be934:4b65a7ea
   devices=/dev/sdb,/dev/sdc,/dev/sdd,/dev/sde metadata=1.2  name=eaglexen-baby:0
[root@eaglexen-baby mnt]#

Romo

@DustinB3403 said:

ARRAY /dev/md0 level=raid10 num-devices=4 metadata=1.2 name=eaglexen-baby:0 UUID=5bd9375b:2166352e:622be934:4b65a7ea
devices=/dev/sdb,/dev/sdc,/dev/sdd,/dev/sde metadata=1.2 name=eaglexen-baby:0

ARRAY /dev/md0 level=raid10 num-devices=4 metadata=1.2 name=eaglexen-baby:0 UUID=5bd9375b:2166352e:622be934:4b65a7ea
devices=/dev/sdb,/dev/sdc,/dev/sdd,/dev/sde

Romo

Don't need the metadata and name again after the devices

DustinB3403

[root@eaglexen-baby mnt]# cat /etc/mdadm.conf 
ARRAY /dev/md0 level=raid10 num-devices=4 metadata=1.2 name=eaglexen-baby:0 UUID=5bd9375b:2166352e:622be934:4b65a7ea devices=/dev/sdb,/dev/sdc,/dev/sdd,/dev/sde

Romo

Yes, seems ok. Reboot and try to check the status of the array once again

DustinB3403

@Romo said:

Yes, seems ok. Reboot and try to check the status of the array once again

Rebooted.

Array found, drives mounted.

DustinB3403

So now that we're back to working condition. We need an entry added to fstab to auto-mount the array.

  GNU nano 1.3.12             File: /etc/fstab                                  

LABEL=root-mhdhrpdq    /         ext3     defaults   1  1
/var/swap/swap.001          swap      swap   defaults   0  0
none        /dev/pts  devpts defaults   0  0
none        /dev/shm  tmpfs  defaults   0  0
none        /proc     proc   defaults   0  0
none        /sys      sysfs  defaults   0  0
none        /sys/fs/cgroup cgroup memory 0 0
/opt/xensource/packages/iso/XenCenter.iso   /var/xen/xc-install   iso9660   loo$
/mnt/raid10   /dev/md0  ext3  defaults 0  0

Romo

Does xencenter see the storage?

DustinB3403

Yes, the Local OBR10 is back on XenCenter.