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Mount Options in Solaris

The "noatime" mount option is useful for running your webserver type of applications, since it's mostly a read-only operation. By eliminating the need to update access times each time a file is accessed, you reduce filesystem activity:

"By default, the file system is mounted with normal access time (atime) recording. If noatime is specified, the file system will ignore access time updates on files, except when they coincide with updates to the ctime or mtime. See stat(2). This option reduces disk activity on file systems where access times are unimportant (for example, a Usenet news spool). noatime turns off access time recording regardless of dfratime or nodfratime."

The "logging" option is a very useful feature that unfortunately was not enabled by default till Solaris 10. By using the "logging" mount option, you enable a filesystem that is journalled on top of the atypical ufs type. From the mount_ufs man page, we see this explanation:

"If logging is specified, then logging is enabled for the duration of the mounted file system. Logging is the process of storing transactions (changes that make up a complete UFS operation) in a log before the transactions are applied to the file system. Once a transaction is stored, the transaction can be applied to the file system later. This prevents file systems from becoming inconsistent, therefore eliminating the need to run fsck. And, because fsck can be bypassed, logging reduces the time required to reboot a system if it crashes, or after an unclean halt. The default behavior is nologging.

The log is allocated from free blocks on the file system, and is sized approximately 1 Mbyte per 1 Gbyte of file system, up to a maximum of 64 Mbytes.

Logging can be enabled on any UFS, including root (/). The log created by UFS logging is continually flushed as it fills up. The log is totally flushed when the file system is unmounted or as a result of the lockfs -f command."

To enable this, simply specify "logging" as an option to mount in /etc/vfstab.

"forcedirectio" option is useful for large files. From the mount_ufs man page, we see this explanation:

"If forcedirectio is specified and supported by the file system, then for the duration of the mount forced direct I/O will be used. If the filesystem is mounted using forcedirectio, then data is transferred directly between user address space and the disk. If the filesystem is mounted using noforcedirectio, then data is buffered in kernel address space when data is transferred between user address space and the disk. forcedirectio is a performance option that benefits only from large sequential data transfers. The default behavior is noforcedirectio."

Recommended Links

Everything Solaris Filesystems Tips and Tricks

Why aren't you logging

Getting to know the Solaris filesystem, Part 1 - SunWorld - May 1999

Reference

mount_ufs

 

-o specific_options

Specify ufs file system specific options in a comma-separated list with no intervening spaces. If invalid options are specified, a warning message is printed and the invalid options are ignored. The following options are available:
 

noatime

By default, the file system is mounted with normal access time (atime) recording. If noatime is specified, the file system will ignore access time updates on files, except when they coincide with updates to the ctime or mtime. See stat(2). This option reduces disk activity on file systems where access times are unimportant (for example, a Usenet news spool).

noatime turns off access time recording regardless of dfratime or nodfratime.
 

dfratime | nodfratime

By default, writing access time updates to the disk may be deferred (dfratime) for the file system until the disk is accessed for a reason other than updating access times. nodfratime disables this behavior.
 

forcedirectio | noforcedirectio

If forcedirectio is specified and supported by the file system, then for the duration of the mount, forced direct I/O will be used. If the filesystem is mounted using forcedirectio, data is transferred directly between user address space and the disk. If the filesystem is mounted using noforcedirectio, data is buffered in kernel address space when data is transferred between user address space and the disk. forcedirectio is a performance option that is of benefit only in large sequential data transfers. The default behavior is noforcedirectio.
 

global | noglobal

If global is specified and supported on the file system, and the system in question is part of a cluster, the file system will be globally visible on all nodes of the cluster. If noglobal is specified, the mount will not be globally visible. The default behavior is noglobal. The global option is mutually exclusive of the nbmand option, described below.
 

intr | nointr

Allow (do not allow) keyboard interrupts to kill a process that is waiting for an operation on a locked file system. The default is intr.
 

largefiles | nolargefiles

If nolargefiles is specified and supported by the file system, then for the duration of the mount it is guaranteed that all regular files in the file system have a size that will fit in the smallest object of type off_t supported by the system performing the mount. The mount will fail if there are any files in the file system not meeting this criterion. If largefiles is specified, there is no such guarantee. The default behavior is largefiles.

If nolargefiles is specified, mount will fail for ufs if the file system to be mounted has contained a large file (a file whose size is greater than or equal to 2 Gbyte) since the last invocation of fsck on the file system. The large file need not be present in the file system at the time of the mount for the mount to fail; it could have been created previously and destroyed. Invoking fsck (see fsck_ufs(1M)) on the file system will reset the file system state if no large files are present. After invoking fsck, a successful mount of the file system with nolargefiles specified indicates the absence of large files in the file system; an unsuccessful mount attempt indicates the presence of at least one large file.
 

logging | nologging

If logging is specified, then logging is enabled for the duration of the mounted file system. Logging is the process of storing transactions (changes that make up a complete UFS operation) in a log before the transactions are applied to the file system. Once a transaction is stored, the transaction can be applied to the file system later. This prevents file systems from becoming inconsistent, therefore eliminating the need to run fsck. And, because fsck can be bypassed, logging reduces the time required to reboot a system if it crashes, or after an unclean halt. The default behavior is nologging.

The log is allocated from free blocks on the file system, and is sized approximately 1 Mbyte per 1 Gbyte of file system, up to a maximum of 64 Mbytes. Logging can be enabled on any UFS, including root (/). The log created sby UFS logging is continually flushed as it fills up. The log is totally flushed when the file system is unmounted or as a result of the lockfs -f command.

m

Mount the file system without making an entry in /etc/mnttab.
 

nbmand | nonbmand

This option specifies that non-blocking mandatory locking semantics should be allowed on this file system. Non-blocking mandatory locking is disallowed by default. If the file system is mounted with the nbmand option, then applications can use the fcntl(2) interface to place non-blocking mandatory locks on files and the system will enforce those semantics. Enabling this option can cause standards conformant applications to see unexpected errors.

Do not use the nbmand option with /, /var and /usr.

The remount option should not be used to change the nbmand disposition of the file system. The nbmand option is mutually exclusive of the global option, described above.
 

onerror = action

This option specifies the action that UFS should take to recover from an internal inconsistency on a file system. Specify action as panic, lock, or umount. These values cause a forced system shutdown, a file system lock to be applied to the file system, or the file system to be forcibly unmounted, respectively. The default is panic.
 

quota

Quotas are turned on for the file system.
 

remount

Remounts a file system with a new set of options. All options not explicitly set with remount revert to their default values.

rq

Read-write with quotas turned on. Equivalent to rw, quota.

ro | rw

Read-only or read-write. Default is rw.

 

suid | nosuid

Allow or disallow setuid/setgid execution. The default is suid. This option also allows/disallows opening any device-special entries that appear within the filesystem.

This option is highly recommended whenever the file system is shared via NFS with the root= option, because, without it, NFS clients could add setuid programs to the server, or create devices that could open security holes.

-O

Overlay mount. Allow the file system to be mounted over an existing mount point, making the underlying file system inaccessible. If a mount is attempted on a pre-existing mount point without setting this flag, the mount will fail, producing the error "device busy".

 

The mount_ufs command supports the xattr flag, to allow the creation and manipulation of extended attributes. See fsattr(5) for a description of extended attributes. The xattr flag is always on.

mount_nfs

-o specific_options

Set file system specific options according to a comma-separated list with no intervening spaces.

acdirmax=n

Hold cached attributes for no more than n seconds after directory update. The default value is 60.

acdirmin=n

Hold cached attributes for at least n seconds after directory update. The default value is 30.

acregmax=n

Hold cached attributes for no more than n seconds after file modification. The default value is 60.

acregmin=n

Hold cached attributes for at least n seconds after file modification. The default value is 3.

actimeo=n

Set min and max times for regular files and directories to n seconds.

bg | fg

If the first attempt fails, retry in the background, or, in the foreground. The default is fg.

forcedirectio | noforcedirectio

If forcedirectio is specified, then for the duration of the mount, forced direct I/O is used. If the filesystem is mounted using forcedirectio, data is transferred directly between client and server, with no buffering on the client. If the filesystem is mounted using noforcedirectio, data is buffered on the client. forcedirectio is a performance option that is of benefit only in large sequential data transfers. The default behavior is noforcedirectio.

grpid

By default, the GID associated with a newly created file obeys the System V semantics; that is, the GID is set to the effective GID of the calling process. This behavior may be overridden on a per-directory basis by setting the set-GID bit of the parent directory; in this case, the GID of a newly created file is set to the GID of the parent directory (see open(2) and mkdir(2)). Files created on file systems that are mounted with the grpid option obeys BSD semantics independent of whether the set-GID bit of the parent directory is set; that is, the GID is unconditionally inherited from that of the parent directory.

hard | soft

Continue to retry requests until the server responds (hard) or give up and return an error (soft). The default value is hard.

intr | nointr

Allow (do not allow) keyboard interrupts to kill a process that is hung while waiting for a response on a hard-mounted file system. The default is intr, which makes it possible for clients to interrupt applications that may be waiting for a remote mount.

noac

Suppress data and attribute caching. The data caching that is suppressed is the write-behind. The local page cache is still maintained, but data copied into it is immediately written to the server.

nocto

Do not perform the normal close-to-open consistency. When a file is closed, all modified data associated with the file is flushed to the server and not held on the client. When a file is opened the client sends a request to the server to validate the client's local caches. This behavior ensures a file's consistency across multiple NFS clients. When -nocto is in effect, the client does not perform the flush on close and the request for validation, allowing the possiblity of differences among copies of the same file as stored on multiple clients.

This option can be used where it can be guaranteed that accesses to a specified file system are made from only one client and only that client. Under such a condition, the effect of -nocto can be a slight performance gain.

port=n

The server IP port number. The default is NFS_PORT. If the port option is specified, and if the resource includes one or more NFS URLs, and if any of the URLs include a port number, then the port number in the option and in the URL must be the same.

posix

Request POSIX.1 semantics for the file system. Requires a mount Version 2 mountd(1M) on the server. See standards(5) for information regarding POSIX.

proto=<netid>

<netid> is a value of network_id field from entry in the /etc/netconfig file. By default, the transport protocol used for the NFS mount is the first available connection oriented transport supported on both the client and the server. If no connection oriented transport is found, then the first available connectionless transport is used. This default behavior can be overridden with the proto=<netid> option.

public

The public option forces the use of the public file handle when connecting to the NFS server. The resource specified may or may not have an NFS URL. See the discussion of URL's and the public option under NFS FILE SYSTEMS for a more detailed discussion.

quota | noquota

Enable or prevent quota(1M) to check whether the user is over quota on this file system; if the file system has quotas enabled on the server, quotas are still checked for operations on this file system.

remount

Remounts a read-only file system as read-write (using the rw option). This option cannot be used with other -o options, and this option works only on currently mounted read-only file systems.

retrans=n

Set the number of NFS retransmissions to n. The default value is 5. For connection-oriented transports, this option has no effect because it is assumed that the transport performs retransmissions on behalf of NFS.

retry=n

The number of times to retry the mount operation. The default for the mount command is 10000.

The default for the automounter is 0, in other words, do not retry. You might find it useful to increase this value on heavily loaded servers, where automounter traffic is dropped, causing unnecessary "server not responding" errors.

ro | rw

resource is mounted read-only or read-write. The default is rw.

rsize=n

Set the read buffer size to n bytes. The default value is 32768 when using Version 3 of the NFS protocol. The default can be negotiated down if the server prefers a smaller transfer size. When using Version 2, the default value is 8192.

sec=mode

Set the security mode for NFS transactions. If sec= is not specified, then the default action is to use AUTH_SYS over NFS Version 2 mounts, or to negotiate a mode over NFS Version 3 mounts. NFS Version 3 mounts negotiate a security mode when the server returns an array of security modes. The client picks the first mode in the array that is supported on the client. Only one mode can be specified with the sec= option. See nfssec(5) for the available mode options.

secure

This option has been deprecated in favor of the sec=dh option.

suid | nosuid

Allow or disallow setuid execution. The default is suid.

timeo=n

Set the NFS timeout to n tenths of a second. The default value is 11 tenths of a second for connectionless transports, and 600 tenths of a second for connection-oriented transports.

vers=<NFS version number>

By default, the version of NFS protocol used between the client and the server is the highest one available on both systems. If the NFS server does not support NFS Version 3 protocol, then the NFS mount uses NFS Version 2 protocol.

wsize=n

Set the write buffer size to n bytes. The default value is 32768 when using Version 3 of the NFS protocol. The default can be negotiated down if the server prefers a smaller transfer size. When using Version 2, the default value is 8192.

xattr | noxattr

Allow or disallow the creation and manipulation of extended attributes. The default is xattr. See fsattr(5) for a description of extended attributes.

 

-O

Overlay mount. Allow the file system to be mounted over an existing mount point, making the underlying file system inaccessible. If a mount is attempted on a pre-existing mount point without setting this flag, the mount fails, producing the error "device busy."

Last modified: June 05, 2008