Re: nfsrvstats.srvrpc_errs rapidly increasing

From: Heinrich Rebehn (rebehn_at_ant.uni-bremen.de)
Date: 05/11/05

  • Next message: George V. Neville-Neil: "Re: kern/76432: [patch] [net/route.h] recursive locking in the network stack" 
    Date: Wed, 11 May 2005 11:07:06 +0200
To: Mohan Srinivasan <mohan_srinivasan@yahoo.com>

    Mohan Srinivasan wrote:
    > Hi,
    >
    > The srvrcp_errs are very likely unrelated to the hangs.
    >
    > nfs_rephead() is called (via the contorted macros nfsm_reply() and
    > friends) from the NFS server routines in nfs_serv.c. The error
    > that was returned by the vnode op called is passed into
    > nfs_rephead(), whence it gets into the NFS reply. The fact that
    > you see these errors go up is not abnormal. In your case, over
    > 90% of these errors are ENOENT.
    >
    > Are you using NFS/TCP ? Can you force the mount to NFS/UDP ?

    Yes, we use TCP. It is strongly recommended for multispeed networks and
    we did have problems with retransmissions using UDP.
    Also, in order to change to UDP for testing purposes, we would have to
    reboot our entire Linux cluster, which is hardly feasible.

    > I have seen a bug in the FreeBSD 5.x NFS server, where in the
    > NFS/TCP case, the stream gets out of sync. This results in the
    > RPC record markers to be completely wrong, confusing clients.
    > Now, I don't know if this bug can cause the Linux client to hang
    > or not, but this is definitely worth eliminating as a factor.
    > The FreeBSD NFS client recovers from this by tearing down the
    > connection and reconnecting, other clients may behave strangely.

    Wouldn't it be better to fix the bug? Is there a problem report on this?

    Some more info on my original problem:
    We have diskless Linux clients that mount their root fs from the FBSD
    server. Most times this works, but sometimes the mount simply hangs and
    i have to issue a "/etc/rc.d/nfsd restart" on the server.

    Any thoughts on this?

    --Heinrich
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  • Next message: George V. Neville-Neil: "Re: kern/76432: [patch] [net/route.h] recursive locking in the network stack"

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