iunique(9) [suse man page]

IUNIQUE(9)							   The Linux VFS							IUNIQUE(9)

NAME

       iunique - get a unique inode number

SYNOPSIS

       ino_t iunique(struct super_block * sb, ino_t max_reserved);

ARGUMENTS

       sb
	   superblock

       max_reserved
	   highest reserved inode number

DESCRIPTION

       Obtain an inode number that is unique on the system for a given superblock. This is used by file systems that have no natural permanent
       inode numbering system. An inode number is returned that is higher than the reserved limit but unique.

BUGS

       With a large number of inodes live on the file system this function currently becomes quite slow.

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010								IUNIQUE(9)

ninode(5)							File Formats Manual							 ninode(5)

NAME

       ninode - maximum number of HFS file system open inodes that can be in memory

VALUES

   Failsafe
   Default
       The  default  value is computed at runtime and depends on the amount of physical memory on the system.  For small memory systems (less than
       1GB), the default is 4880.  For systems with more than 1GB of memory, the default is 8192, or 8K.

   Allowed values
       The minimum value allowed is 14.  The maximum value allowed is memory limited.

       Specify a positive integer value.

DESCRIPTION

       The tunable defines the number of slots in the HFS inode table.	This number limits the number of open inodes that can be in memory for HFS
       file  systems  at  any  given  time.   The inode table is used as a cache memory.  For performance reasons the most recent (number of) open
       inodes are kept in main memory.	The table is hashed.

       Each unique open file has an open inode associated with it.  Therefore, the larger the number of unique open files, the larger should be.

   Who Is Expected to Change This Tunable?
       This tunable is only relevant on systems where there are HFS file systems mounted.  Note that the use of HFS file systems is  being  depre-
       cated in HP-UX.

   Restrictions on Changing
       This tunable is static.	Any changes to the value of this tunable will require system reboot to take effect.

   When Should the Value of This Tunable Be Raised?
       This value of many need to be raised on systems running applications that expect large numbers of open files on HFS file systems.

   What are the Side Effects of Raising the Value?
       The HFS inode table is statically allocated, therefore will consume more memory if the value of this tunable is raised.

   When Should the Value of This Tunable Be Lowered?
       The value of can be lowered on systems with small or no mounted HFS file systems, to reduce memory consumption.

   What are the Side Effects of Lowering the Value?
       The number of open HFS inodes that can be kept in memory is bound to the new lower limit.

   What Other Tunable Values Should Be Changed at the Same Time?
       None.

WARNINGS

       All  HP-UX kernel tunable parameters are release specific.  This parameter may be removed or have its meaning changed in future releases of
       HP-UX.

       The tunable is relevant only on systems with HFS file systems.  Note that the use of HFS file systems is being deprecated in  HP-UX.   This
       and other HFS related tunable parameters may be removed from future HP-UX releases.

       Installation  of  optional  kernel  software, from HP or other vendors, may cause changes to tunable parameter values.  After installation,
       some tunable parameters may no longer be at the default or recommended values.  For information about the effects of installation  on  tun-
       able  values,  consult  the documentation for the kernel software being installed.  For information about optional kernel software that was
       factory installed on your system, see at

AUTHOR

       was developed by HP.

SEE ALSO

       kctune(1M), sam(1M), gettune(2), settune(2).

							     Tunable Kernel Parameters							 ninode(5)