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HISTORY
Written by Landon Curt Noll (chongo@toad.com) and Rich $alz (rsalz@uunet.uu.net) for InterNetNews.
SEE ALSO
control.ctl(5), ctlinnd(8), expire(8), innd(8), news.daily(8), nntpsend(8), newslog(8)
nfs—NFS fstab format and options.
SYNOPSIS
/etc/fstab
DESCRIPTION
The fstab file contains information about which filesystems to mount where and with what options. For NFS mounts, it contains the server name and exported server directory to mount from, the local directory that is the mount point, and the NFS-specific options that control the way the filesystem is mounted. Here is an example from an /etc/fstab file from an NFS mount.
server:/usr/local/pub /pub nfs rsize=8192,wsize=8192,timeo=14,intr
OPTIONS
| rsize=n | The number of bytes NFS uses when reading files from an NFS server. The default value is dependent on the kernel, currently 1024 bytes. (However, throughput is improved greatly by asking for rsize=8192.) |
| wsize=n | The number of bytes NFS uses when writing files to an NFS server. The default value is dependent on the kernel, currently 1024 bytes. (However, throughput is improved greatly by asking for wsize=8192.) |
| timeo=n | The value in tenths of a second before sending the first retransmission after an RPC time-out. The default value is 7 tenths of a second. After the first time-out, the time-out is doubled after each successive time-out until a maximum time-out of 60 seconds is reached or the enough retransmissions have occurred to cause a major time-out. Then, if the filesystem is hard mounted, each new time-out cascade restarts at twice the initial value of the previous cascade, again doubling at each retransmission. The maximum time-out is always 60 seconds. Better overall performance may be achieved by increasing the time-out when mounting on a busy network, to a slow server, or through several routers or gateways. |
| retrans=n | The number of minor time-outs and retransmissions that must occur before a major time-out occurs. The default is 3 time-outs. When a major time-out occurs, the file operation is either aborted or a "server not responding" message is printed on the console. |
| acregmin=n | The minimum time in seconds that attributes of a regular file should be cached before requesting fresh information from a server. The default is 3 seconds. |
| acregmax=n | The maximum time in seconds that attributes of a regular file can be cached before requesting fresh information from a server. The default is 60 seconds. |
| acdirmin=n | The minimum time in seconds that attributes of a directory should be cached before requesting fresh information from a server. The default is 30 seconds. |
| acdirmax=n | The maximum time in seconds that attributes of a directory can be cached before requesting fresh information from a server. The default is 60 seconds. |
| actimeo=n | Using actimeo sets all of acregmin, acregmax, acdirmin, and acdirmax to the same value. There is no default value. |
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| retry=n | The number of times to retry a backgrounded NFS mount operation before giving up. The default value is 10000 times. |
| namlen=n | When an NFS server does not support version 2 of the RPC mount protocol, this option can be used to specify the maximum length of a filename that is supported on the remote filesystem. This is used to support the POSIX pathconf functions. The default is 255 characters. |
| port=n | The numeric value of the port to connect to the NFS server on. If the port number is 0 (the default) then query the remote host's port mapper for the port number to use. If the remote host's NFS daemon is not registered with its port mapper, the standard NFS port number 2049 is used instead. |
| mountport=n | The numeric value of the mountd port. |
| mounthost=name | The name of the host running mountd. |
| mountprog=n | Use an alternate RPC program number to contact the mount daemon on the remote host. This option is useful for hosts that can run multiple NFS servers. The default value is 100005, which is the standard RPC mount daemon program number. |
| mountvers=n | Use an alternate RPC version number to contact the mount daemon on the remote host. This option is useful for hosts that can run multiple NFS servers. The default value is version 1. |
| nfsprog=n | Use an alternate RPC program number to contact the NFS daemon on the remote host. This option is useful for hosts that can run multiple NFS servers. The default value is 100003, which is the standard RPC NFS daemon program number. |
| nfsvers=n | Use an alternate RPC version number to contact the NFS daemon on the remote host. This option is useful for hosts that can run multiple NFS servers. The default value is version 2. |
| bg | If the first NFS mount attempt times out, continue trying the mount in the background. The default is to not to background the mount on time-out but to fail. |
| fg | If the first NFS mount attempt times out, fail immediately. This is the default. |
| soft | If an NFS file operation has a major time-out, then report an I/O error to the calling program. The default is to continue retrying NFS file operations indefinitely. |
| hard | If an NFS file operation has a major time-out, then report "server not responding" on the console and continue retrying indefinitely. This is the default. |
| intr | If an NFS file operation has a major time-out and it is hard mounted, then allow signals to interrupt the file operation and cause it to return EINTR to the calling program. The default is to not allow file operations to be interrupted. |
| posix | Mount the NFS filesystem using POSIX semantics. This allows an NFS filesystem to properly support the POSIX pathconf command by querying the mount server for the maximum length of a filename. To do this, the remote host must support version 2 of the RPC mount protocol. Many NFS servers support only version 1. |
| nocto | Suppress the retrieval of new attributes when creating a file. |
| noac | Disable all forms of attribute caching entirely. This extracts a server performance penalty, but it allows two different NFS clients to get reasonably good results when both clients are actively writing to a common filesystem on the server. |
| tcp | Mount the NFS filesystem using the TCP protocol instead of the default UDP protocol. Many NFS severs only support UDP. |
| udp | Mount the NFS filesystem using the UDP protocol. This is the default. All the non-value options have corresponding nooption forms. For example, nointr means don't allow file operations to be interrupted. |
FILES
/etc/fstab