setcache

The dynamic view caches consist mostly of data retrieved from the VOB and enable the view_server to respond faster to RPCs from client machines. When a view_server process is started, it chooses its cache size from the first of the following sources to yield a value:

• The dynamic view's cache size, which is set with mkview -cachesize or setcache -view -cachesize and stored in the file view-storage-dir/.view (on the -cache line)
• The view_server host's default cache size, which is set with setcache -view -host and stored as a decimal number in the file /var/adm/devops/clearcase/config/view_cache_size (UNIX and Linux) or ccase-home-dir\var\config\view_cache_size (Windows)
• The site-wide cache default, which is set with setcache -view -site or setsite and stored in the site config registry
• The default value: 4096 KB.

The dynamic view cache size is allocated among the individual caches. When specifying a cache size, keep the following guidelines in mind:

• The value cannot be smaller than 512 KB.
• Do not specify a value larger than the amount of physical memory on the server host that you want to dedicate to this view.
• Verify your changes by using getcache to check the hit rates and utilization percentages periodically to see whether they have improved.

A host's MVFS caches are used to optimize file system performance:

• The directory name cache accelerates name translation. This cache is partitioned into three areas, each of which can be tuned with one of the setcache -mvfs options:
  • Directory files (-dirdnc)
  • Nondirectory files (-regdnc)
  • Names not found (ENOENT) (-noentdnc)
    Note: If processes are actively using the directory name cache, you may see the following error message when trying to resize it:

    cleartool: Error: Unable to set some current MVFS parameters
    to requested values because caches are in active use.

    Ask users to stop using ClearCase actively (that is, keep their view contexts, but stop manipulating files) and enter the setcache command again.

• The attribute cache accelerates access to file metadata (for example, by the stat and access system calls, which are frequently called during make or clearmake operations). The -vobfreemax and -vobfreemin options establish the high- and low-water marks for the attribute cache for VOB and view-private files that are not currently open; the -mnmax option sets this value for both opened and unopened files.
• The cleartext cache accelerates the open system call for files in a VOB and view-private files. The -cvpfreemax and -cvpfreemin options establish the high- and low-water marks for this cache. This cache is never larger than the size of the attribute cache.
• The RPC handles cache accelerates RPCs to the dynamic view. The -rpchandles option sets the size of this cache; the value ought to be the maximum simultaneous number of RPCs expected from your host. If this value is too small, the getcache -mvfs command recommends that you adjust its size.

For more information about using setcache, see the discussion of client performance tuning in the DevOps Code ClearCase Administrator's Guide.

Default

None.

-vie/w

Sets the cache size for a single view. This immediately changes the cache size; you do not need to kill and restart the view_server.

-vie/w -hos/t

Sets the default cache size for the current host.

-vie/w -sit/e

Sets the site-wide default size for view caches.

-mvfs

Sets cache sizes for the MVFS, either temporarily or persistently.

-zone

Specifies the MVFS cache size for a nonglobal zone on Oracle Solaris systems running on SPARC and x86 computers. For more information on using this option, see the administrator help topics. For general information on nonglobal zones, refer to Oracle documentation.

-expected_zone_count cnt

Specifies the number of Solaris zones (global, non-global, branded) that are expected to run the MVFS.

The recommended value is the total number of zones (global and non-global) that are expected to run DevOps Code ClearCase on that computer. ClearCase uses this value to compute the scaling factor and cache sizes for the MVFS. Specifically, the total available memory on the system is divided by the number of expected zones, and then algorithms are applied to set the scaling factor and cache sizes. If the expected number of zones is not specified, the scaling factor in the global zone is computed based on the total system memory size, and the scaling factor in the other zones is set to one by default. With an unspecified number of zones, the appropriate cache sizes for the MVFS might not be allocated equitably across zones, which can result in non-optimal performance.

Default

None.

-def/ault

With -view, removes the -cache line from the .view file. This immediately sets the size of the view cache to (in priority order) the host size, the site-wide size, or the default size. (SeeDescription.)

With -view -host, deletes the /var/adm/devops/clearcase/config/view_cache_size (UNIX and Linux) or ccase-home-dir\var\config\view_cache_size (Windows) file.

With -view -site, removes the value for the site-wide cache from the registry.

When used with setcache -mvfs, -default must be used with the -persistent or -persistent_only option, and restores MVFS cache values to installed defaults. (See Description.) Setting certain values that force changes in other values may cause setcache to print a message explaining that the new values will not take effect until you restart the MVFS.

-cac/hesize size

Specifies a size for the view_server cache. size must be an integer value of bytes, optionally followed by the letter k to specify kilobytes or m to specify megabytes; for example, 800k or 3m.

Default

None.

-cvi/ew

Sets the cache size for the current view.

view-tag

Specifies the view for which the cache size is changed.

Default

When you set the sitewide view cache size with -view -site, setcache prompts you for the registry password.

-pas/sword registry-password

Specifies the sitewide registry password.

Default

None. You must specify at least one option. cnt and val must be integer values. For information about default and suggested values, see the DevOps Code ClearCase Administrator's Guide. Setting certain values that force changes in other values may cause setcache to print a message explaining that the new values will not take effect until you restart the MVFS.

-per/sistent

When this option is specified with the options -readdir_blocks or -scalefactor, then the options are set persistently, but are not effective until the MVFS is restarted. In other words, in the contexts of -readdir_blocks or -scalefactor, this option is identical to -persistent_only.

In all other cases, this option specifies that all options are applied immediately and also set persistently. If you do not specify -persistent, options revert to their former values when the MVFS is restarted.

-persistent_only

Specifies that all options will be set persistently but will not take effect until the MVFS is restarted.

NOTE: This option is not supported for Solaris nonglobal zones.

-reg/dnc cnt

Sets the number of regular file DNC entries.

-noe/ntdnc cnt

Sets the number of ENOENT (file not found) DNC entries.

-dir/dnc cnt

Sets the number of directory DNC entries.

-vob/freemax cnt

Sets the maximum number of free (unused) attribute cache entries. This is a subset of the total specified by -mnmax.

-cvp/freemax cnt

Sets the number of entries in the cleartext cache.

-rpc/handles cnt

Sets the number of RPC handles cached by the MVFS.

-vobfreemin cnt

Sets the minimum number of mnodes to keep on the VOB free list.

-cvpfreemin cnt

Sets the minimum number of mnodes to keep on the cleartext free list.

-rea/ddir_blocks cnt

Sets the number of blocks cached for each directory read by the MVFS. Valid only with -persistent or -persistent_only.

-mnmax cnt

Sets the initial number of mnodes cached by the MVFS. (Several internal values are derived from this value, but will not be changed until after the MVFS is restarted.)

-sca/lefactor val

Sets the scaling factor used to initialize the MVFS with more memory for better performance. Valid only with -persistent or -persistent_only.

-cto

Enables close-to-open consistency checking.

-ncto

Disables close-to-open consistency checking.

-aca/che

Enables attribute caching.

-nac/ache

Disables attribute caching.

-dnc/ache

Enables directory name caching.

-ndnc/ache

Disables directory name caching.

-rlc/ache

Enables readlink caching.

-nrlc/ache

Disables readlink caching.

-rdrc/ache

Enables the read-directory cache, which accelerates the reading of directory entries.

-nrdrc/ache

Disables the read-directory cache.

-rvc/ache

Enables root version caching.

-nrvc/ache

Disables root version caching.