vfs_readahead(8) [suse man page]
VFS_READAHEAD(8) System Administration tools VFS_READAHEAD(8) NAME
vfs_readahead - pre-load the kernel buffer cache SYNOPSIS
vfs objects = readahead DESCRIPTION
This VFS module is part of the samba(7) suite. This vfs_readahead VFS module detects read requests at multiples of a given offset (hex 0x80000 by default) and then tells the kernel via either the readahead system call (on Linux) or the posix_fadvise system call to pre-fetch this data into the buffer cache. This module is useful for Windows Vista clients reading data using the Windows Explorer program, which asynchronously does multiple file read requests at offset boundaries of 0x80000 bytes. The offset multiple used is given by the readahead:offset option, which defaults to 0x80000. The size of the disk read operations performed by vfs_readahead is determined by the readahead:length option. By default this is set to the same value as the readahead:offset option and if not set explicitly will use the current value of readahead:offset. This module is stackable. OPTIONS
readahead:offset = BYTES The offset multiple that causes readahead to be requested of the kernel buffer cache. readahead:length = BYTES The number of bytes requested to be read into the kernel buffer cache on each readahead call. The following suffixes may be applied to BYTES: o K - BYTES is a number of kilobytes o M - BYTES is a number of megabytes o G - BYTES is a number of gigabytes EXAMPLES
[hypothetical] vfs objects = readahead VERSION
This man page is correct for version 3.0.25 of the Samba suite. AUTHOR
The original Samba software and related utilities were created by Andrew Tridgell. Samba is now developed by the Samba Team as an Open Source project similar to the way the Linux kernel is developed. Samba 3.5 06/18/2010 VFS_READAHEAD(8)
Check Out this Related Man Page
VFS_CACHEPRIME(8) VFS_CACHEPRIME(8) NAME
vfs_cacheprime - prime the kernel file data cache SYNOPSIS
vfs objects = cacheprime DESCRIPTION
This VFS module is part of the samba(7) suite. The vfs_cacheprime VFS module reads chunks of file data near the range requested by clients in order to make sure the data is present in the kernel file data cache at the time when it is actually requested by clients. The size of the disk read operations performed by vfs_cacheprime is determined by the cacheprime:rsize option. All disk read operations are aligned on boundaries that are a multiple of this size. Each range of the file data is primed at most once during the time the client has the file open. This module is stackable. OPTIONS
cacheprime:rsize = BYTES The number of bytes with which to prime the kernel data cache. The following suffixes may be applied to BYTES: o K - BYTES is a number of kilobytes o M - BYTES is a number of megabytes o G - BYTES is a number of gigabytes EXAMPLES
For a hypothetical disk array, it is necessary to ensure that all read operations are of size 1 megabyte (1048576 bytes), and aligned on 1 megabyte boundaries: [hypothetical] vfs objects = cacheprime cacheprime:rsize = 1M CAVEATS
cacheprime is not a a substitute for a general-purpose readahead mechanism. It is intended for use only in very specific environments where disk operations must be aligned and sized to known values (as much as that is possible). VERSION
This man page is correct for version 3.0.25 of the Samba suite. AUTHOR
The original Samba software and related utilities were created by Andrew Tridgell. Samba is now developed by the Samba Team as an Open Source project similar to the way the Linux kernel is developed. VFS_CACHEPRIME(8)