3.5.1 Matrix Server Release Notes

PolyServe Release Notes 21

9789 Client times out before it can mount exported filesystems

If the clientʹs mount command times out consistently (for

example, for every retry of a backgrounded mount), one

possible cause is that the client IP address cannot be resolved to

names at the server. The server mountd may take longer

attempting to translate the client address than the client mount

is prepared to wait.

To resolve this problem, ensure that the server can translate the

clientʹs IP addresses to names. This can be done in any of several

ways: by adding entries to the serverʹs /etc/hosts file, by

deploying a DNS in-addr.arpa zone that covers the client

addresses, or by avoiding the use of nonroutable private

addresses (for example, do not use network 192.168/16 without

private DNS in-addr support).

10577 Clients may occasionally experience errors during failover

Due to the inherent unreliable nature of the NFS protocol, NFS

RPC requests or replies may occasionally be lost. The NFS client

will then retry the request. This situation occasionally results in

duplicate NFS RPC requests sent to the NFS server.

Normally, a duplicate NFS RPC is detected in the NFS replay

cache and a response sent immediately without attempting to

execute the command a second time. This prevents unlinks, for

example, from generating spurious file-not-found or stale-file-

handle errors.

However, if an NFS RPC arrives on a node that subsequently

fails before the reply can be sent, the client will retry the NFS

RPC. This retransmission will arrive at the backup (gaining)

node, will not be detected as a replay in the replay cache, and

will be processed a second time. RPCʹs that have non-

idempotent results (such as unlink, rename, and create) will

then generate an error back to the clientʹs application.

Read and write operations will not show this problem.

Defect Description