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Re: X-RAID vertical expansion incomplete

Retired_Member
Not applicable

X-RAID vertical expansion incomplete

ReadyNAS 314 running OS 6.4.0

Was previously running with 4x1TB drives. As we came close to filling that up, ordered 4x2TB drives for vertical expansion.

 

Replaced the disk in bay 1, waited for resync to complete, no problems.

Replaced the disk in bay 2, waited for resync to complete, no problems. After that it began a second lengthy operation (I can't remember the exact verbiage used, but I'm fairly confident that this was expanding the capacity to make use of the two newer disks). No problems.

Replaced the disk in bay 3, waited for resync to complete, no problems. Waited for expansion to complete, no problems.

Replaced the disk in bay 4, waited for resync to complete, no problems. I did not immediately notice that the final expansion did not take place.

 

This unit has SSH enabled, so when I noticed that the capacity wasn't what I expected (it reports 4.45 TB capacity instead of the expected 5.24 TB), I poked around a bit and found this:

 

root@netgear:~# btrfs filesystem show /data
Label: '5e276904:data'  uuid: 7e35ca18-0d2e-45f7-aa31-a82747bea137
        Total devices 2 FS bytes used 2.61TiB
        devid    1 size 2.71TiB used 2.63TiB path /dev/md127
        devid    2 size 1.82TiB used 171.00GiB path /dev/md126

btrfs-progs v4.1.2

root@netgear:~# mdadm --detail /dev/md127
/dev/md127:
        Version : 1.2
  Creation Time : Tue Jul  9 03:32:40 2002
     Raid Level : raid5
     Array Size : 2915731968 (2780.66 GiB 2985.71 GB)
  Used Dev Size : 971910656 (926.89 GiB 995.24 GB)
   Raid Devices : 4
  Total Devices : 4
    Persistence : Superblock is persistent

    Update Time : Tue Sep  6 17:50:49 2016
          State : clean
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           Name : 5e276904:data-0  (local to host 5e276904)
           UUID : e33eecc1:f9ec98cf:0bae86e1:28333094
         Events : 3594

    Number   Major   Minor   RaidDevice State
       4       8        3        0      active sync   /dev/sda3
       5       8       19        1      active sync   /dev/sdb3
       6       8       35        2      active sync   /dev/sdc3
       7       8       51        3      active sync   /dev/sdd3

root@netgear:~# mdadm --detail /dev/md126
/dev/md126:
        Version : 1.2
  Creation Time : Tue Aug  9 17:01:44 2016
     Raid Level : raid5
     Array Size : 1953245824 (1862.76 GiB 2000.12 GB)
  Used Dev Size : 976622912 (931.38 GiB 1000.06 GB)
   Raid Devices : 3
  Total Devices : 4
    Persistence : Superblock is persistent

    Update Time : Tue Sep  6 17:50:49 2016
          State : clean
 Active Devices : 3
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 1

         Layout : left-symmetric
     Chunk Size : 64K

           Name : 5e276904:data-1  (local to host 5e276904)
           UUID : df0953ba:a63f8097:563d7345:af6846f6
         Events : 3031

    Number   Major   Minor   RaidDevice State
       0       8        4        0      active sync   /dev/sda4
       1       8       20        1      active sync   /dev/sdb4
       2       8       36        2      active sync   /dev/sdc4

       3       8       52        -      spare   /dev/sdd4

root@netgear:~# mdadm --examine /dev/sdd4
/dev/sdd4:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : df0953ba:a63f8097:563d7345:af6846f6
           Name : 5e276904:data-1  (local to host 5e276904)
  Creation Time : Tue Aug  9 17:01:44 2016
     Raid Level : raid5
   Raid Devices : 3

 Avail Dev Size : 1953245896 (931.38 GiB 1000.06 GB)
     Array Size : 1953245824 (1862.76 GiB 2000.12 GB)
  Used Dev Size : 1953245824 (931.38 GiB 1000.06 GB)
    Data Offset : 262144 sectors
   Super Offset : 8 sectors
   Unused Space : before=262056 sectors, after=72 sectors
          State : clean
    Device UUID : 3de39043:50f0af6e:cbcdc324:337612b0

    Update Time : Fri Aug 12 01:47:27 2016
  Bad Block Log : 512 entries available at offset 72 sectors
       Checksum : 1e90ec50 - correct
         Events : 3031

         Layout : left-symmetric
     Chunk Size : 64K

   Device Role : spare
   Array State : AAA ('A' == active, '.' == missing, 'R' == replacing)

It looks like the device kept the original RAID array as-is with the ~3TB storage capactiy in the first 1TB of each drive, built a second RAID 5 array using the next 1TB of each drive, and then used BTRFS features to join them into a single filesystem (which is fine). What I don't understand is why the second RAID array (/dev/md126) is treating the top 1TB of the fourth disk (/dev/sdd4) as a 'spare' rather than an active disk. All four new disks are identical Western Digital Reds.

 

We have good backups and so in principle I could just wipe the array and start over, however this array is actively used in a business and the associated downtime is not particularly appealing, especially since I'm not often physically on-site with the unit.

Model: RN31400|ReadyNAS 300 Series 4- Bay
Message 1 of 9

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mdgm-ntgr
NETGEAR Employee Retired

Re: X-RAID vertical expansion incomplete

Yes, but you do want to check the disks are healthy, partitions are the correct size etc. before doing that.


Doing it yourself is at your own risk.

View solution in original post

Message 7 of 9

All Replies
mdgm-ntgr
NETGEAR Employee Retired

Re: X-RAID vertical expansion incomplete

That's easily fixed.

 

Btw 6.4.0 is old firmware. Once the problem is fixed you may wish to update the firmware.

Message 2 of 9
omicron_persei8
Luminary

Re: X-RAID vertical expansion incomplete

You could try to simply reboot the NAS. Otherwise, I would fail, remove then add sdd4 from/to md126. If you're not comfortable with fixing the RAID yourself, you could try to contact NETGEAR Support.
Message 3 of 9
omicron_persei8
Luminary

Re: X-RAID vertical expansion incomplete

Actually, you might just need to grow the number of raid devices of md126 from 3 to 4.
Message 4 of 9
mdgm-ntgr
NETGEAR Employee Retired

Re: X-RAID vertical expansion incomplete


@omicron_persei8 wrote:
Actually, you might just need to grow the number of raid devices of md126 from 3 to 4.

Assuming everything is fine, yes. Once the RAID is expanded the volume should automatically expand.

Message 5 of 9
Retired_Member
Not applicable

Re: X-RAID vertical expansion incomplete


@mdgm wrote:

@omicron_persei8 wrote:
Actually, you might just need to grow the number of raid devices of md126 from 3 to 4.

Assuming everything is fine, yes. Once the RAID is expanded the volume should automatically expand.


Am I correct that this would be accomplished simply by running 

mdadm --grow /dev/md126 --raid-devices=4

from SSH (assuming the system is in all other ways healthy)? Or are there any special considerations introduced by ReadyNAS or BTRFS?

 

--- EDIT ---

 

Nevermind, just saw your PM, mdgm. Thanks for the info, I'll give it a shot after some additional checks.

 

Message 6 of 9
mdgm-ntgr
NETGEAR Employee Retired

Re: X-RAID vertical expansion incomplete

Yes, but you do want to check the disks are healthy, partitions are the correct size etc. before doing that.


Doing it yourself is at your own risk.

Message 7 of 9
Retired_Member
Not applicable

Re: X-RAID vertical expansion incomplete

Just wanted to say, everything seemed to work out well. Various health checks such as smartctl (and others I no longer recall) came back clean, and, after running the suggest mdadm command the volume expansion began as expected. It completed without issue.

 

Thanks for your assistance.

Message 8 of 9
JennC
NETGEAR Employee Retired

Re: X-RAID vertical expansion incomplete

Hello Retired_Member,

 

We are glad that it works now. 

 

We encourage you to post any suggestion, comments or questions you have that you feel like posting. We appreciate your contribution.


Regards,

Message 9 of 9
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