NFS(5) NFS(5) (NAME) nfs - NFS (SYNOPSIS) /etc/fstab (DESCRIPTION) NFS (mount) . NFS Sun Microsystems . NFS . NFS 3 4.0 4.1 4.2 NFS . mount(8) . /etc/fstab mount(8) ( NFS) . /etc/fstab . NFS /etc/fstab NFS . NFS . : server:path /mountpoint fstype option,option,... 0 0 (:) . . (unqualified) (FQDN) IPv4 IPv6 . IPv6 - (link-local) - (site-local) . IPv6 ipv6(7) . fstype "nfs" . "nfs4" /etc/fstab . (MOUNT OPTIONS) mount(8) . defaults /etc/fstab . (Options supported by all versions) NFS . nfsvers=n NFS NFS . . 4.2 . vers=n nfsvers . . soft / softerr / hard NFS (timeout) NFS . ( hard ) NFS . soft softerr NFS retrans NFS NFS EIO ( soft) ETIMEDOUT ( softerr) . : "" (soft) . soft softerr . NFS TCP retrans soft softerr . softreval / nosoftreval NFS retrans NFS () . (unmount) . softreval soft retrans . hard . : nosoftreval hard soft . intr / nointr . 2.6.25 . timeo=n ( ) NFS NFS . NFS TCP timeo 600 ( ) . NFS (linear backoff) : timeo . NFS UDP ( READ WRITE) ( FSINFO) timeo . timeo . . NFS . timeo . TCP RDMA 600 ( ) . UDP 60 ( ) . retrans=n NFS . retrans NFS UDP TCP . NFS retrans "server not responding" ( ) ( hard ). rsize=n READ NFS NFS . (payload) READ NFS rsize . NFS ,, ( ) . rsize (page size) . rsize . . rsize rsize . rsize mount(8) /etc/mtab . rsize /proc/mounts . wsize=n WRITE NFS NFS . WRITE NFS wsize . NFS ,, ( ) . rsize wsize . wsize . . wsize . wsize mount(8) /etc/mtab . wsize /proc/mounts . ac / noac ( ) . ( ac ) . NFS . NFS . . noac . noac (synchronous) . . noac (cache coherence) NFS . . << >> . acregmin=n ( ) NFS . NFS . << >> . acregmax=n ( ) NFS . NFS . << >> . acdirmin=n ( ) NFS . NFS . acdirmax=n ( ) NFS . . actimeo=n actimeo acregmin acregmax acdirmin acdirmax . NFS . bg / fg mount(8) . fg mount(8) . "" (foreground) fg bg . bg mount(8) . . "" (background) . mount(8) . NFS /etc/fstab NFS . automounter ( automount(8) ). nconnect=n TCP . / (NIC) . nconnect . nconnect pNFS . rdirplus / nordirplus READDIRPLUS NFS . NFS READDIR READDIRPLUS READDIRPLUS . READDIR . rdirplus={none|force} "force" NFS READDIRPLUS . "none" nordirplus . retry=n mount(8) NFS . ( ) . mount(8) . . UDP timeo retrans . TCP TCP . sec=flavors . . sec= . (flavors) : none sys krb5 krb5i krb5p. << >> . sharecache / nosharecache . . sharecache . nosharecache . . 2.6.18 nosharecache . . resvport / noresvport NFS NFS (privileged) . resvport NFS . noresvport . 2.6.28 . NFS NFS . << >> . lookupcache=mode . mode all none pos positive . 2.6.28 . NFS LOOKUP NFS . positive () . negative () . all . pos positive . none . . << >> . fsc / nofsc () FS-Cache . FS-Cache cachefilesd(8) Documentation/filesystems/caching . nofsc . sloppy sloppy mount.nfs -s . xprtsec=policy (TLS) NFS . policy none tls mtls . none NFS . tls RPC-with-TLS . mtls RPC-with-TLS . tls mtls RPC-with-TLS . xprtsec= xprtsec=none . noalignwrite . NFS " " (lost writes) . . NFS (Options for NFS versions 2 and 3 only) NFS . proto=netid netid NFS . : udp udp6 tcp tcp6 rdma rdma6. 6 IPv6 TI-RPC . IPv4 . retrans timeo . . NFS mount(8) rpcbind mountd . netid TCP mount(8) NFS TCP . netid UDP UDP . NFS UDP << >> . proto mount(8) . << >> . udp udp proto=udp . . NFS UDP << >> . tcp tcp proto=tcp . . rdma rdma proto=rdma . port=n () NFS . NFS . NFS NFS rpcbind . rpcbind NFS rpcbind NFS . mountport=n mountd . mountd . mount(8) mountd rpcbind . rpcbind mountd rpcbind mountd . NFS rpcbind . mountproto=netid NFS mountd NFS . netid udp tcp IPv4 TI-RPC mount.nfs udp6 tcp6 IPv6 . NFS . proto mountd NFS . mountd . mountproto proto << >> . mounthost=name mountd . mount(8) mountd NFS . mountvers=n RPC mountd . NFS . NFS . namlen=n . . . NFS . pathconf(3) . lock / nolock NLM . ( lock ) NLM . nolock . . NLM NFS /var nolock /var NLM . nolock NFS NLM . cto / nocto << >> (close-to-open) . ( cto ) close-to-open . nocto . nocto . << >> . acl / noacl NFSACL . NFSACL Solaris (ACL) . NFSACL NFS . acl noacl NFS NFSACL . NFSACL . << >> . local_lock=mechanism flock POSIX . mechanism all flock posix none . 2.6.37 . NFS . . . none . all flock POSIX . flock flock POSIX NLM . posix POSIX flock NLM . flock NFS 2.6.12 'local_lock=flock' . NFS Samba Samba flock . NFS 2.6.12 flock POSIX . : 'local_lock' 'nolock'/'lock' . NFS (Options for NFS version 4 only) NFS 4.0 . proto=netid netid NFS . : tcp tcp6 rdma rdma6. tcp6 IPv6 TI-RPC . IPv4 . NFS TCP NFS TCP . << >> . minorversion=n (minor version) . NFSv4 " " NFS . 2.6.38 . "minorversion=1" NFSv4 . vers= . vers=4.1 vers=4,minorversion=1 . port=n NFS . NFS . NFS NFS 2049 rpcbind . NFS rpcbind . NFS NFS rpcbind . rpcbind NFS rpcbind NFS . cto / nocto << >> (close-to-open) NFS . cto nocto close-to-open . . << >> . clientaddr=n.n.n.n clientaddr=n:n:...:n IPv4 ( ) IPv6 - NFS (callback) 4.0 NFS . (hang) . IPv4_ANY (0.0.0.0) IPv6 any NFS (delegations) . mount(8) . . . 4.1 4.2 NFS TCP . 4.0 NFS . migration / nomigration (TSM) NFSv4 . NFSv4 TSM migration . . nomigration NFS . . . NFSv4 TSM . max_connect=n nconnect IP max_connect IP NFSv4.1+ ( session trunking) . (client ID) RPC . trunkdiscovery / notrunkdiscovery NFSv4.1+ trunkdiscovery GETATTR fs_locations . EXCHANGE_ID session trunking . max_connect . notrunkdiscovery . nfs4 (nfs4 FILE SYSTEM TYPE) nfs4 NFSv4 . NFSv4 nfsvers . (MOUNT CONFIGURATION FILE) mount /etc/nfsmount.conf . nfsmount.conf(5) . (EXAMPLES) NFS nfs nfsvers=3 . NFS nfs nfsvers=4 nfs4 . /etc/fstab mount NFS : server:/export /mnt nfs defaults 0 0 NFS TCP Kerberos 5 : server:/export /mnt nfs4 sec=krb5 0 0 NFS TCP Kerberos 5 : server:/export /mnt nfs4 sec=krb5p:krb5i 0 0 /usr NFS : server:/export /usr nfs ro,nolock,nocto,actimeo=3600 0 0 NFS - IPv6 : [fe80::215:c5ff:fb3e:e2b1%eth0]:/export /mnt nfs defaults 0 0 (TRANSPORT METHODS) NFS (Remote Procedure Calls) RPC NFS . RPC (endianness) . RPC . mount(8) NFS NFS . . NFS UDP . NFS UDP . NFS . UDP MTU NFS ( jumbo frames ) . rsize wsize NFS ( ) . MTU . TCP NFS . . TCP . NFS . NFS TCP . NFS TCP . ( retrans) (network partition) . TCP rsize wsize MTU . mountproto (Using the mountproto mount option) NFS NFS . NFS rpcbind NFS mountd (NLM) NFS . NFS proto mountproto udp tcp . (NSM) UDP NSM UDP TCP . NFS ( NFSACL) NFS . NFS UDP mountd TCP NLM NFS . mount(8) . . bg mount . proto udp tcp mountproto mountd NLM NFS . mountproto proto udp tcp mountd mount NFS TCP . mountproto proto ( udp tcp) mountproto mountd proto ( udp tcp) NFS . . proto udp tcp mountproto mount () . NFS UDP (Using NFS over UDP on high-speed links) NFS UDP . (IP fragment reassembly) . NFS UDP ( ) . IP (fragmentation) . IP IP ID UDP IP ID . UDP . (reassembly) . () . . NFS IP ID . : IP ID . IP - UDP UDP UDP . UDP ( ). (silent data corruption) . . 100Mbit/s IP ID . NFS TCP TCP . NFS UDP : (Jumbo frames): . NFS UDP 8K . . MTU . (Lower reassembly timeout): IP ID . ( ) /proc/sys/net/ipv4/ipfrag_time . IPID . (DATA AND METADATA COHERENCE) () . NFS (WAN) . NFS . (Close-to-open cache consistency) . A . B . NFS NFS GETATTR ACCESS . NFS . NFS . NFS close(2) . CTO . nocto . (Weak cache consistency) . NFS " " ( WCC ) . . ( ) . (Attribute caching) noac . . . noac . . noac " " . noac (race conditions) . NFS . . O_DIRECT . (File timestamp maintenance) NFS (atime ctime mtime). NFS . NFS . NFS NFS . NFS NFS . POSIX NFS NFS mtime ctime . mtime stat(2) . atime . NFS atime atime . NFS atime . mount(8) . atime/noatime diratime/nodiratime relatime/norelatime strictatime / nostrictatime NFS . /proc/mounts relatime NFS atime relatime . (Directory entry caching) NFS NFS LOOKUP . positive () . ( ENOENT ) negative () . NFS mtime . mtime LOOKUP . mtime . mtime acdirmin acdirmax noac . . . lookupcache . 2.6.28 NFS . . NFS lookupcache=positive . . lookupcache=none . NFS . noac NFS . sync (The sync mount option) NFS sync ( sync async mount(8) ). sync async ( async ) NFS : . sync(2) msync(2) fsync(3) . close(2) . fcntl(2) . . sync . . O_SYNC sync . NFS (Using file locks with NFS) (NLM) NFS . - (NSM) - . NFS NFS NLM NSM . NLM NSM . NFS (FQDN) NFS . NLM (advisory locks) . NFS fcntl(2) F_GETLK F_SETLK . NFS flock(2) . NLM NFS NLM nolock . NLM NFS /var nolock /var NLM . nolock . NFS (NFS version 4 caching features) NFS . : (change attributes) (file delegation). NFS . . . (file delegation) NFS . ( /callback) . . : (read) (write). . . . . . . (SECURITY CONSIDERATIONS) NFS NFS RPC . NFS . RPC ( uid ) (gid ) . ( "in the clear") . NFS . . NFS . RPC . . RPCGSS . sec NFS . sec=krb5 RPC . . (Kerberos) . rpc.gssd(8) . Kerberos : krb5i krb5p. krb5i RPC . krb5p RPC . . NFS (NFS version 4 filesystem crossing) . . (pseudo-fs) pseudo-fs . NFS (NFS version 4 Leases) NFS (lease) . . . NFSv4 . . . . nfs4.nfs4_unique_id . (principal) . . NFS . . . Kerberos NFS ( /etc/krb5.keytab ) Kerberos . . host/ nfs/ /etc/krb5.keytab rpc.gssd(8) . Kerberos keytab AUTH_SYS UID 0 . (Using non-privileged source ports) NFS NFS . () IP . () (TCP UDP) IP . NFS (privileged) . . (root) . sysctl ssh . NFS . NFS AUTH_SYS NFS UID GID . NFS UID GID NFS . (spoof) . NFS . . AUTH_SYS NFS . NFS . (export option) . Kerberos . (Mounting through a firewall) NFS IP . NFS mount(8) NFS . NFS portmapper rpcbind . rpcbind : RPC RPC rpcbind () . NFS () NLM . rpcbind . rpcbind NFS NFS . mountd mountport mount(8) . TCP UDP . NFS (NFS Access Control Lists) Solaris NFS POSIX (ACL) . NFSACL (mode bits) . NFS . NFSACL NFS . NFS ACL POSIX . ACL NFS ACL POSIX ACL POSIX NFS . (THE REMOUNT OPTION) rw sync remount NFS . mount(8) . NFS . NFS . NFS noac . noac sync NFS actimeo=0 . (Unmounting after a remount) NFS umount NFS MNT . mount NFS . . : mount -o remount,ro /mnt ro NFS /mnt . (FILES) /etc/fstab /etc/nfsmount.conf NFS (NOTES) 2.4.7 NFS NFS TCP . 2.4.20 NFS close- to-open . 2.4.22 NFS RTT NFS UDP . 2.6.0 NFS NFS . 2.6.8 NFS rsize wsize . CONFIG_NFS_V2 CONFIG_NFS_V3 CONFIG_NFS_V4 CONFIG_NFS_V4_1 CONFIG_NFS_V4_2 . (SEE ALSO) fstab(5) mount(8) umount(8) mount.nfs(5) umount.nfs(5) exports(5) nfsmount.conf(5) netconfig(5) ipv6(7) nfsd(8) sm-notify(8) rpc.statd(8) rpc.idmapd(8) rpc.gssd(8) rpc.svcgssd(8) kerberos(1) RFC 768 UDP. RFC 793 TCP. RFC 1813 NFS. RFC 1832 XDR. RFC 1833 RPC bind. RFC 2203 RPCSEC GSS API. RFC 7530 4.0 NFS. RFC 5661 4.1 NFS. RFC 7862 4.2 NFS. nfs-utils NFS(5)