Hi,   I am seeing a similar kind of issue on my namenode servers. When I tried to restart my namenode, it failed initially with permission issues on /data1/dfs/nn. The group identifier didn't exist in the list of groups I had. So, I changed the permissions on the /data1/dfs/nn and restarted it. This fixed the issue with /data1/dfs/nn but later starting throwing similar kind of errors with /data2/dfs/nn. I repeated the same steps on /data2/dfs/nn hoping that this will fix the issue.But no luck. For the same name node, why is it different for the data dirs. Any pointers ? ... View more