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HP-UX Reference > Nncsize(5)Tunable Kernel ParametersHP-UX 11i Version 2: December 2007 Update |
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NAMEncsize — number of Directory Name Lookup Cache (DNLC) entries DESCRIPTIONTo speed up the search through directories in the kernel, there is a memory resident cache of directories called the Directory Name Lookup Cache (DNLC). During a filename lookup in the kernel, any directories or files encountered are retained in the DNLC for future reference. The ncsize tunable dictates the number of entries in the DNLC, which is statically allocated at system boot time. Therefore, the larger the value of ncsize, the larger the number of directory/file entries that can be kept cached in memory for filename lookup. Restrictions on ChangingThis tunable is static. Any changes to the value of this tunable will require system reboot before taking effect. When Should the Value of This Tunable Be Raised?The value may need to be raised to improve filename lookup performance when running applications which require large numbers of filename access. When Should the Value of This Tunable Be Lowered?The value can be lowered to limit the number of entries in the DNLC and reduce memory consumption. WARNINGSAll 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 tunable values, consult the documentation for the kernel software being installed. For information about optional kernel software that was factory installed on your system, see HP-UX Release Notes at http://docs.hp.com. |
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