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NexentaStor 1.1.0 (Default branch)
11-12-2008
NexentaStor leverages the ZFS file system and is optimized for use in 2nd-tier NAS and iSCSI applications requiring open, low cost, high performance storage as well as dramatically simplified provisioning, expansion, backup, replication, and archiving. It is also used as a primary NAS in businesses that wish to expand at closer to commodity pricing. It supports unlimited snapshots, snapshot mirroring (replication), block level mirroring, integrated search, and easy management of extremely large storage pools. License: Other/Proprietary License with Free Trial Changes:|
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dnlc_hash_locks(5) File Formats Manual dnlc_hash_locks(5) NAME
dnlc_hash_locks - number of locks for the Directory Name Lookup Cache (DNLC) VALUES
Failsafe Default Allowed values The minimum value allowed is The maximum value allowed is The value is further constrained in that it must be be a power of 2, and it must be equal to or less than one-eighth the number of DNLC entries Specify a positive integer value. DESCRIPTION
To speed up the search through directories in the kernel, there is a memory resident cache of directories called the During a filename lookup in the kernel, any directories or files encountered are retained in the DNLC for future reference. The DLNC is managed in a Least Recently Used fashion. The dictates the number of lock groups that will be used to manage the directory entries in the DNLC hash chains. Who Is Expected to Change This Tunable? HP-UX system administrators. Restrictions on Changing This tunable is static. Any changes to the value of this tunable require a system reboot before taking effect. When Should the Value of This Tunable Be Raised? The value may need to be raised to reduce lock contention and improve filename lookup performance when running applications which require large numbers of file name accesses. What are the Side Effects of Raising the Value? More system memory will be consumed to allocate locks for the DNLC. When Should the Value of This Tunable Be Lowered? The value can be lowered to limit the number of locks allocated for the DNLC and to reduce memory consumption. What are the Side Effects of Lowering the Value? Less system memory will be consumed for the DNLC locks upon system reboot. Operations requiring filename lookup (for example, (see open(2)) may experience performance degradation. What Other Tunable Values Should Be Changed at the Same Time? The value of must be equal to or greater than eight times the value of 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 HP. SEE ALSO
kctune(1M), smh(1M), gettune(2), settune(2). Tunable Kernel Parameters dnlc_hash_locks(5)