WARNING : 2120 NFS share ends up read-only.

I'm having problems with a new 2120 (6.1.1) using 4*4TB disks HUS724040ALE640.

I am trying to use a new feature introduced in PHD backup 6.5 to create a replica backup store. The store is 4.6TB on disk and is on a older 3100 it makes use of hard linked files quite extensively ( 20TB of data without).

During the copy process the PHD vba will hang with the following.

Aug 28 14:45:43 phdvb archived[1007]: [ tid #0x3ef ] error: Unable to rename block [/dd/blocks/1048576/md5/none/56/4d/564d8b5a818cd199b185bac0a8f6298b.tmp] - Read-only file system

A reboot of the NAs will allow it to proceed a little before hanging again. I have tested again using a old Thecus as the archive store and left it running it has got to 260Gb archived and is still proceeding. So I know its not a PHD issue.

Also once this problem occurs I cant modify any of the settings for the NFS share via the GUI. Commit failed with 100203001

any pointers for what log files I should look in.

Hang on have i run into this

Files with hard links in other directories have multiple reference items, one for each parent directory. Files with hard links in the same directory pack all of the links' filenames into the same reference item. This was a design flaw that limited the number of same-directory hard links to however many could fit in a single tree block. (On the default block size of 4KB, an average filename length of 8 bytes and a per-filename header of 4 bytes, this would be less than 350.) Applications which made heavy use of same-directory hard links, such as git, GNUS, GMame and BackupPC were later observed to fail after hitting this limit.[47] The limit was eventually removed[48] (and as of October 2012 has been merged[49] pending release in Linux 3.7) by introducing spillover extended reference items to hold hard link filenames which could not otherwise fit.

Anyone know if the btrfs used in the readyos 6 is the newer release which this fixed?