rsize=n
The number of bytes nfs4 uses when reading files from the server. The rsize is negotiated between the server and client to determine the largest block size that both can support. The value specified by this option is the maximum size that could be used; however, the actual size used may be smaller. Note: Setting this size to a value less than the largest supported block size will adversely affect performance.
wsize=n
The number of bytes nfs4 uses when writing files to the server. The wsize is negotiated between the server and client to determine the largest block size that both can support. The value specified by this option is the maximum size that could be used; however, the actual size used may be smaller. Note: Setting this size to a value less than the largest supported block size will adversely affect performance.
timeo=n
The value in tenths of a second before sending the first retransmission after an RPC timeout. The default value depends on whether proto=udp or proto=tcp is in effect (see below). The default value for UDP is 7 tenths of a second. The default value for TCP is 60 seconds. After the first timeout, the timeout is doubled after each successive timeout until a maximum timeout of 60 seconds is reached or the enough retransmissions have occured to cause a major timeout. Then, if the filesystem is hard mounted, each new timeout cascade restarts at twice the initial value of the previous cascade, again doubling at each retransmission. The maximum timeout is always 60 seconds.
retrans=n
The number of minor timeouts and retransmissions that must occur before a major timeout occurs. The default is 5 timeouts for proto=udp and 2 timeouts for proto=tcp. When a major timeout 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.
retry=n
The number of minutes to retry an NFS mount operation in the foreground or background before giving up. The default value for forground mounts is 2 minutes. The default value for background mounts is 10000 minutes, which is roughly one week.
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 portmapper for the port number to use. If the remote host's NFS daemon is not registered with its portmapper, the standard NFS port number 2049 is used instead.
proto=n
Mount the NFS filesystem using a specific network protocol instead of the default TCP protocol. Valid protocol types are udp and tcp. Many NFS version 4 servers only support the TCP protocol.
clientaddr=n
On a multi-homed client, this causes the client to use a specific callback address when communicating with an NFS version 4 server. This option is currently ignored.
sec=mode
Same as sec=mode for the nfs filesystem type (see above).
bg
If an NFS mount attempt times out, retry the mount in the background. After a mount operation is backgrounded, all subsequent mounts on the same NFS server will be backgrounded immediately, without first attempting the mount. A missing mount point is treated as a timeout, to allow for nested NFS mounts.
fg
If the first NFS mount attempt times out, retry the mount in the foreground. This is the complement of the bg option, and also the default behavior.
soft
If an NFS file operation has a major timeout 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 timeout 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 timeout and it is hard mounted, then allow signals to interupt the file operation and cause it to return EINTR to the calling program. The default is to not allow file operations to be interrupted.
nocto
Suppress the retrieval of new attributes when creating a file.
noac
Disable attribute caching, and force synchronous writes. This extracts a server performance penalty but it allows two different NFS clients to get reasonable good results when both clients are actively writing to common filesystem on the server.
nosharecache
As of kernel 2.6.18, it is no longer possible to mount the same same filesystem with different mount options to a new mountpoint. It was deemed unsafe to do so, since cached data cannot be shared between the two mountpoints. In consequence, files or directories that were common to both mountpoint subtrees could often be seen to be out of sync following an update.
