[CentOS] System Hang on busy NFS server

[John Doe]

From: James A. Peltier <jpeltier at sfu.ca>

> On a busy NFS server I've started receiving the following error messages and 
> the system hangs with high load but no work being done.  The system is a Dell 
> R510 with 12 x 3TB drives in a RAID-50 configuration.  The RAID-50 device is a 
> full disk LVM (no partitions) and one large (36TB) data volume and the system is 
> running CentOS 6.4 fully patched for OS and firmware.
> 
> Anyone have any hints as to what might be causing this.  It looks to me like the 
> system is starting to swap and then failing and then XFS starts to throw a hissy 
> fit because it can't start allocating pages for it's buffers.  
> Eventually then the system just deadlocks.  I'm just looking for someone to 
> confirm my findings and let me know if this is a bug or not.
> 
> I've posted the dmesg output onto pastebin http://pastebin.com/YQbhsN6a
> 
> Any help is very much appreciated!

Google seems to suggest to maybe perhaps look at:
  sysctl vm.min_free_kbytes

JD