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miky76

Banned

From: Italy

Registered: 2011-10-27

Posts: 137

Converting RAID 1 in RAID 5

I'm trying to change from RAID1 to RAID 5,
i'm following this article for do this, http://amandine.aupetit.info/42/raid1-to-raid5/

but I'm having some trouble about it

I had 2x1TB disks in raid 1 that now are full

I bought a new 3TB HD where I've made 1TB partition, now I want to add this partition to the other 2 in raid5

the 3 partitions involved are

- sdb1
- sdc1
- sda5

so I've tried to do this

mdadm /dev/md127 --fail /dev/sdc1
mdadm /dev/md127 -r /dev/sdc1 
mdadm --create /dev/md1 -l5 -n2 /dev/sdc1 /dev/sda5
pvcreate /dev/md1
vgextend data /dev/md1
pvdisplay
 

[root@artemide ~]# pvdisplay
  Couldn't find device with uuid 90AtlC-KW7z-K99i-Yh5R-mFzR-Pf8t-2MCZV1.
  --- Physical volume ---
  PV Name               /dev/md127
  VG Name               data
  PV Size               931.51 GiB / not usable 4.54 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              238466
  Free PE               0
  Allocated PE          238466
  PV UUID               u72Z9t-mr3r-niHt-ylLh-cTsq-LfV4-0haYqC

  --- Physical volume ---
  PV Name               unknown device
  VG Name               data
  PV Size               931.39 GiB / not usable 1.50 MiB
  Allocatable           yes
  PE Size               4.00 MiB
  Total PE              238435
  Free PE               238435
  Allocated PE          0
  PV UUID               90AtlC-KW7z-K99i-Yh5R-mFzR-Pf8t-2MCZV1

where the first is the raid 1 with only one disk in it (sdb1) and the second should be the raid 5 made with sdc1 and sda5.

what is not clear to me is

- why PV Name is unknown device and not /dev/md1?
- why the PV size is different in the 2 RAID structures?
- why it's saying "Couldn't find device with uuid 90AtlC-KW7z-K99i-Yh5R-mFzR-Pf8t-2MCZV1."

because I've backed up all the datas, I can destroy everything and start again,
but I would like to know why I cannot make it work

miky76

Banned

From: Italy

Registered: 2011-10-27

Posts: 137

Re: Converting RAID 1 in RAID 5

I've solved part of the problem

[root@artemide ~]# vgreduce --removemissing data
  Couldn't find device with uuid 90AtlC-KW7z-K99i-Yh5R-mFzR-Pf8t-2MCZV1.
  Wrote out consistent volume group data

[root@artemide ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/md127
  VG Name               data
  PV Size               931.51 GiB / not usable 4.54 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              238466
  Free PE               0
  Allocated PE          238466
  PV UUID               u72Z9t-mr3r-niHt-ylLh-cTsq-LfV4-0haYqC

this should be the RAID 1 where only sdb1 is in still in it