[CentOS] errors in logs - kernel: XFS (dm-7): xlog_space_left: head behind tail

Tue Mar 20 22:13:57 UTC 2012
John R Pierce <pierce at hogranch.com>

On 03/20/12 2:54 PM, Gregory Machin wrote:
> I have a CentOS 6.2 virtual machine in a vmware ESXi 4.0 host 4G Ram 4
> virtaul cpus and with about 4 TB of disk space formatted with XFS .
> I'm seeing a lot of :
>
> Mar 21 10:49:42 nzhmlfpr05 kernel: XFS (dm-4): xlog_space_left: head behind tail
> Mar 21 10:49:42 nzhmlfpr05 kernel:  tail_cycle = 129, tail_bytes = 20163072
> Mar 21 10:49:42 nzhmlfpr05 kernel:  GH   cycle = 129, GH   bytes = 20162880
> Mar 21 10:49:42 nzhmlfpr05 kernel: XFS (dm-7): xlog_space_left: head behind tail
> Mar 21 10:49:42 nzhmlfpr05 kernel:  tail_cycle = 5, tail_bytes = 333417984
> Mar 21 10:49:42 nzhmlfpr05 kernel:  GH   cycle = 5, GH   bytes = 333417792
> Mar 21 10:49:42 nzhmlfpr05 kernel: XFS (dm-7): xlog_space_left: head behind tail
> Mar 21 10:49:42 nzhmlfpr05 kernel:  tail_cycle = 5, tail_bytes = 333417984
> Mar 21 10:49:42 nzhmlfpr05 kernel:  GH   cycle = 5, GH   bytes = 333417792
>
> What would casue this ? A quick google , I found a post that indicated
> I should unmount and mount the file systems. I have live production
> data on this machine so I need to be careful. What is the best
> solution ?

what sort of physical disk storage is this vm using?   I'm wondering if 
perhaps this storage is unreliable with regards to write commits, or 
write ordering.





-- 
john r pierce                            N 37, W 122
santa cruz ca                         mid-left coast