Update nfs(5) manpage - timeo for NFS/TCP

[nfs-utils.git] / utils / mount / nfs.man

diff --git a/utils/mount/nfs.man b/utils/mount/nfs.man
index 1b8676849a916afa65c95b8bc751554ebc11e0b0..ce40933b2b42b2d503831c1de43c16d82608c6b6 100644 (file)
--- a/utils/mount/nfs.man
+++ b/utils/mount/nfs.man
@@ -46,11 +46,10 @@ files on this mount point.
 The fifth and sixth fields on each line are not used
 by NFS, thus conventionally each contain the digit zero. For example:
 .P
 The fifth and sixth fields on each line are not used
 by NFS, thus conventionally each contain the digit zero. For example:
 .P

-.SP
-.NF
-.TA 2.5i +0.75i +0.75i +1.0i
+.nf
+.ta 8n +14n +14n +9n +20n

        server:path     /mountpoint     fstype  option,option,...       0 0
        server:path     /mountpoint     fstype  option,option,...       0 0

-.FI
+.fi

 .P
 The server's hostname and export pathname
 are separated by a colon, while
 .P
 The server's hostname and export pathname
 are separated by a colon, while


@@ -113,12 +112,16 @@ option may mitigate some of the risks of using the
 option.
 .TP 1.5i
 .BI timeo= n
 option.
 .TP 1.5i
 .BI timeo= n

-The time (in tenths of a second) the NFS client waits for a
-response before it retries an NFS request. If this
-option is not specified, requests are retried every
-60 seconds for NFS over TCP.
-The NFS client does not perform any kind of timeout backoff
-for NFS over TCP.
+The time in deciseconds (tenths of a second) the NFS client waits for a
+response before it retries an NFS request.
+.IP
+For NFS over TCP the default
+.B timeo
+value is 600 (60 seconds).
+The NFS client performs linear backoff: After each retransmission the 
+timeout is increased by
+.BR timeo 
+up to the maximum of 600 seconds.

 .IP
 However, for NFS over UDP, the client uses an adaptive
 algorithm to estimate an appropriate timeout value for frequently used
 .IP
 However, for NFS over UDP, the client uses an adaptive
 algorithm to estimate an appropriate timeout value for frequently used


@@ -752,8 +755,8 @@ If
 is specified, the client assumes that POSIX locks are local and uses NLM
 sideband protocol to lock files when flock locks are used.
 .IP
 is specified, the client assumes that POSIX locks are local and uses NLM
 sideband protocol to lock files when flock locks are used.
 .IP

-To support legacy flock behavior similar to that of NFS clients < 2.6.12, use
-'local_lock=flock'. This option is required when exporting NFS mounts via
+To support legacy flock behavior similar to that of NFS clients < 2.6.12, 
+use 'local_lock=flock'. This option is required when exporting NFS mounts via

 Samba as Samba maps Windows share mode locks as flock. Since NFS clients >
 2.6.12 implement flock by emulating POSIX locks, this will result in
 conflicting locks.
 Samba as Samba maps Windows share mode locks as flock. Since NFS clients >
 2.6.12 implement flock by emulating POSIX locks, this will result in
 conflicting locks.


@@ -900,40 +903,40 @@ The following example from an
 file causes the mount command to negotiate
 reasonable defaults for NFS behavior.
 .P
 file causes the mount command to negotiate
 reasonable defaults for NFS behavior.
 .P

-.NF
-.TA 2.5i +0.7i +0.7i +.7i
+.nf
+.ta 8n +16n +6n +6n +30n

        server:/export  /mnt    nfs     defaults        0 0
        server:/export  /mnt    nfs     defaults        0 0

-.FI
+.fi

 .P
 Here is an example from an /etc/fstab file for an NFS version 2 mount over UDP.
 .P
 .P
 Here is an example from an /etc/fstab file for an NFS version 2 mount over UDP.
 .P

-.NF
-.TA 2.5i +0.7i +0.7i +.7i
+.nf
+.ta 8n +16n +6n +6n +30n

        server:/export  /mnt    nfs     nfsvers=2,proto=udp     0 0
        server:/export  /mnt    nfs     nfsvers=2,proto=udp     0 0

-.FI
+.fi

 .P
 Try this example to mount using NFS version 4 over TCP
 with Kerberos 5 mutual authentication.
 .P
 .P
 Try this example to mount using NFS version 4 over TCP
 with Kerberos 5 mutual authentication.
 .P

-.NF
-.TA 2.5i +0.7i +0.7i +.7i
+.nf
+.ta 8n +16n +6n +6n +30n

        server:/export  /mnt    nfs4    sec=krb5        0 0
        server:/export  /mnt    nfs4    sec=krb5        0 0

-.FI
+.fi

 .P
 This example can be used to mount /usr over NFS.
 .P
 .P
 This example can be used to mount /usr over NFS.
 .P

-.NF
-.TA 2.5i +0.7i +0.7i +.7i
+.nf
+.ta 8n +16n +6n +6n +30n

        server:/export  /usr    nfs     ro,nolock,nocto,actimeo=3600    0 0
        server:/export  /usr    nfs     ro,nolock,nocto,actimeo=3600    0 0

-.FI
+.fi

 .P
 This example shows how to mount an NFS server
 using a raw IPv6 link-local address.
 .P
 .P
 This example shows how to mount an NFS server
 using a raw IPv6 link-local address.
 .P

-.NF
-.TA 2.5i +0.7i +0.7i +.7i
+.nf
+.ta 8n +40n +5n +4n +9n

        [fe80::215:c5ff:fb3e:e2b1%eth0]:/export /mnt    nfs     defaults        0 0
        [fe80::215:c5ff:fb3e:e2b1%eth0]:/export /mnt    nfs     defaults        0 0

-.FI
+.fi

 .SH "TRANSPORT METHODS"
 NFS clients send requests to NFS servers via
 Remote Procedure Calls, or
 .SH "TRANSPORT METHODS"
 NFS clients send requests to NFS servers via
 Remote Procedure Calls, or


@@ -1523,32 +1526,54 @@ of Access Control Lists that are semantically richer than POSIX ACLs.
 NFS version 4 ACLs are not fully compatible with POSIX ACLs; as such,
 some translation between the two is required
 in an environment that mixes POSIX ACLs and NFS version 4.
 NFS version 4 ACLs are not fully compatible with POSIX ACLs; as such,
 some translation between the two is required
 in an environment that mixes POSIX ACLs and NFS version 4.

-.SH FILES
-.TP 1.5i
-.I /etc/fstab
-file system table
-.SH BUGS
-The generic
-.B remount
-option is not fully supported.
-Generic options, such as
-.BR rw " and " ro
-can be modified using the
-.B remount
-option,
-but NFS-specific options are not all supported.
+.SH "THE REMOUNT OPTION"
+Generic mount options such as
+.BR rw " and " sync
+can be modified on NFS mount points using the
+.BR remount
+option.
+See
+.BR mount (8)
+for more information on generic mount options.
+.P
+With few exceptions, NFS-specific options
+are not able to be modified during a remount.

 The underlying transport or NFS version
 cannot be changed by a remount, for example.
 The underlying transport or NFS version
 cannot be changed by a remount, for example.

+.P

 Performing a remount on an NFS file system mounted with the
 .B noac
 option may have unintended consequences.
 The
 .B noac
 Performing a remount on an NFS file system mounted with the
 .B noac
 option may have unintended consequences.
 The
 .B noac

-option is a mixture of a generic option,
+option is a combination of the generic option

 .BR sync ,
 .BR sync ,

-and an NFS-specific option
+and the NFS-specific option

 .BR actimeo=0 .
 .BR actimeo=0 .

+.SS "Unmounting after a remount"
+For mount points that use NFS versions 2 or 3, the NFS umount subcommand
+depends on knowing the original set of mount options used to perform the
+MNT operation.
+These options are stored on disk by the NFS mount subcommand,
+and can be erased by a remount.
+.P
+To ensure that the saved mount options are not erased during a remount,
+specify either the local mount directory, or the server hostname and
+export pathname, but not both, during a remount.  For example,

 .P
 .P

+.NF
+.TA 2.5i
+       mount -o remount,ro /mnt
+.FI
+.P
+merges the mount option
+.B ro
+with the mount options already saved on disk for the NFS server mounted at /mnt.
+.SH FILES
+.TP 1.5i
+.I /etc/fstab
+file system table
+.SH BUGS

 Before 2.4.7, the Linux NFS client did not support NFS over TCP.
 .P
 Before 2.4.20, the Linux NFS client used a heuristic
 Before 2.4.7, the Linux NFS client did not support NFS over TCP.
 .P
 Before 2.4.20, the Linux NFS client used a heuristic