RN104 Wrong total disk Size

[fencer019]

I have a RN104 with 2 drives, 1x4TB and 1x2TB configured as JBOD. I pulled out the 2TB and cloned the disk to a new 6TB and resized the partition to take the full size of the disk.

When the 6TB was plugged into the device, ReadyNAS correctly identified the disk as a 6TB but the total space available remained the same.

Is there a way to fix this?

[fencer019 · Accepted solution]

I managed to allocate the space by running 

btrfs filesystem resize 2:max /data

Thanks @Sandshark and @StephenB for your valubale help!

[StephenB]

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/@fencer019 wrote:

 I pulled out the 2TB and cloned the disk to a new 6TB and resized the partition to take the full size of the disk.

When the 6TB was plugged into the device, ReadyNAS correctly identified the disk as a 6TB but the total space available remained the same.

Is there a way to fix this?

---

I think all you need to do is manually expand the btrfs file system via ssh.

Since the volume is named data, the command would be btrfs filesystem resize max /data

If you haven't used ssh before:

1. first enable it in system->settings->services
2. then log in as root (for instance, enter ssh root@NAS-IP-ADDRESS from the windows search bar (using the real NAS IP address of course).  The password is the same as your NAS admin password.

This is definitely done at your own risk.

[Sandshark]

How did you re-size the partition?  The ReadyNAS JBOD still uses MDADM RAID, it just creates RAIDs without redundancy.  If you didn't also expand the RAID, the file system won't expand because it's mounted on the RAID, not directly on the partition.  What does cat /proc/mdstat return from ssh?  Or alternately, what's the content of mdstat.log from the downloaded logs?

[fencer019]

This is the output from cat /proc/mdstat

Personalities : [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md124 : active raid1 sdd3[0]
      3902166784 blocks super 1.2 [1/1] [U]
      bitmap: 3/30 pages [12KB], 65536KB chunk

md125 : active raid1 sda3[0]
      971911808 blocks super 1.2 [1/1] [U]

md126 : active raid1 sdc3[0]
      3902167808 blocks super 1.2 [1/1] [U]

md127 : active raid1 sdb3[0]
      5855670784 blocks super 1.2 [1/1] [U]

md1 : active raid10 sda2[0] sdd2[3] sdc2[2] sdb2[1]
      1044480 blocks super 1.2 512K chunks 2 near-copies [4/4] [UUUU]

md0 : active raid1 sdd1[0] sda1[5](S) sdc1[4] sdb1[3]
      4190208 blocks super 1.2 [3/3] [UUU]

[fencer019]

btrfs device usage /data

/dev/md124, ID: 1
Device size: 3.63TiB
Device slack: 0.00B
Data,single: 3.49TiB
Metadata,single: 8.00MiB
Metadata,RAID1: 3.00GiB
Metadata,DUP: 16.00GiB
System,single: 4.00MiB
System,RAID1: 32.00MiB
System,DUP: 16.00MiB
Unallocated: 133.33GiB

/dev/md127, ID: 2
Device size: 5.45TiB
Device slack: 3.64TiB
Data,single: 1.66TiB
Metadata,RAID1: 3.00GiB
Metadata,DUP: 20.00GiB
System,RAID1: 32.00MiB
Unallocated: 134.36GiB

[Sandshark]

Since you didn't give details on all your drives, I'm guessing a bit, but md127 does appear to be 6TB.  So expanding the BTRFS file system as @StephenB suggested should be all that's necessary.  But I think he got the command backwards btrfs filesystem resize /data max (assuming the volume name is data), though maybe it doesn't matter.

[StephenB]

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@Sandshark wrote:

 But I think he got the command backwards btrfs filesystem resize /data max (assuming the volume name is data), though maybe it doesn't matter.

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The man page says btrfs filesystem resize max <path>.  https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-filesystem  So /data should be last.

[Sandshark]

Must not matter.  My notes from when I did it myself before (which usually turns out to be unnecessary) have it the other way ands another user with a similar issue just had it work.

I suspect that ReadyNASOS is not recognizing it needs to expand because the extra space was added "in the middle", but the manual expand should work.  I've actually never seen any reported "slack" space, but BTRFS knows it's there, so should be able to expand into it.

Note that doing a balance after space is added is usually a good idea, though it only seems to be really important if you've added an entire device to the volume.

[fencer019 · Accepted solution]

I managed to allocate the space by running 

btrfs filesystem resize 2:max /data

Thanks @Sandshark and @StephenB for your valubale help!