Hello,
Right now I'm having this issue on my cluster:
On NameNode web interface at the bottom of the page is table:
NameNode Storage
Storage Directory	Type	State
/srv/dfs/name	IMAGE_AND_EDITS	Failed

I have had this issue before, and I rebooted Hadoop, but lost many files.
What can I do now that I won't lose files since last backup, and what 
this warning actually means?
Any help would be greatly appreciated.
--
Wojciech Langiewicz