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Full Discussion: File Handles
Top Forums UNIX for Advanced & Expert Users File Handles Post 5159 by Neo on Wednesday 8th of August 2001 08:11:16 AM
Old 08-08-2001
You mean 'file descriptors' (FDs) I think. The total number of FDs are kernel parameters. Depending on what UNIX flavor you are running, the kernel documentation and souce code has this info. Some systems are easier than other to reconfigure.

Also, there are formulas to change these parameters because raising or lowering one key kernel parameter effects others (like a balance or scale.... commonly referred to as a design trade-off.)

So, as you know, you can't just make this parameter 100000000000 without seriously impacting (in a negative way) your system performance.
 

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nfs4_max_transfer_size(5)					File Formats Manual					 nfs4_max_transfer_size(5)

NAME
nfs4_max_transfer_size - control the size of the data portion of a NFS version 4 read, write, readdir, or readdirplus request VALUES
Failsafe Default Allowed values Recommended values A warning will be issued at runtime if the tunable is set to a value greater than 1048576 since this is outside the tested limits. This is not a serious warning but just an information message for the administrator. DESCRIPTION
controls the maximum size of the data portion of a NFS version 4 read, write, readdir, or readdirplus request. This parameter controls both the maximum size of a request that the server returns as well as the maximum size of a request that the client generates. Who Is Expected to Change This Tunable? Distributed file system administrators should examine this value if they want to decrease or increase the default size of a NFS packet. Restrictions on Changing The tunable is dynamic; however, the transfer size for a file system is set when the file system is mounted. To affect a particular file system, unmount and mount the file system after changing this parameter. The actual NFS version 4 transfer size is controlled by these tunable parameters: and The actual transfer size will depend on the tunable with the smallest value. For NFS version 4 traffic increase and to the same value to increase the transfer size. To decrease the transfer size, just changing is sufficient. When Should the Value of This Tunable Be Raised? An increase in the transfer size will result in fewer requests to the NFS server at the expense of system resources on both the NFS client and NFS server. What Are the Side Effects of Raising the Value? An increase in system resources on both the NFS client and NFS server. When Should the Value of This Tunable Be Lowered? In the event of NFS communication failures, the value should be changed back to the default value. What Are the Side Effects of Lowering the Value? An increase in NFS version 4 network traffic caused by an increase in the number of I/O requests. 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. 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 Sun Microsystems, Inc. SEE ALSO
kctune(1M), sam(1M), gettune(2), settune(2), nfs4_bsize(5), nfs4_max_transfer_size_cots(5), values(5). Tunable Kernel Parameters nfs4_max_transfer_size(5)
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