Jason Ralph wrote:
Hello List,
We currently have in production a two node cluster with a shared SAS
storage device. Both nodes are running RHEL5 AP and are connected
directly to the storage device via SAS. We also have configured a
high availability NFS service directory that is being exported out and
is mounted on multiple other linux servers.
The problem that I am seeing is:
FIle and folders that are using the GFS filesystem and live on the
storage device are mysteriously getting lost. My first thought was
that maybe one of our many users has deleted them. So I have revoked
the users privilleges and it is still happening. My other tought was
that a rsync script may have overwrote these files or deleted them. I
have stopped all scripting and crons and it has happened again.
Can someone help me with a command or a log to view that would show me
where any of these folders may have gone? Or has anyone else ever run
into this type of data loss using the similar setup?
I don't (or "didn't") have adequate involvements with RHEL5 GFS. I may
not know enough to response. However, ......
Before RHEL 5.1 and/or community version 2.6.22 kernels, NFS lock (via
flock, fcntl, etc from client ends) is not populated into filesystem
layer. It only reaches Linux VFS layer (local to one particular server).
If your file access needs to get synchronized by either flock or posix
fcntl *between multiple hosts (NFS servers)*, data loss could occur.
Newer versions of RHEL and 2.6.22-and-after kernels should have the fixes.
There was an old write-up in section 4.1 of
"http://people.redhat.com/wcheng/Project/nfs.htm"; about this issue.
-- Wendy
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