LDKBMWNG parameter: Difference between revisions
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When an anticipatory write for a modified buffer completes, the buffer is immediately reusable. </p> | When an anticipatory write for a modified buffer completes, the buffer is immediately reusable. </p> | ||
<p> | <p> | ||
If <var>[[NLRUQG_parameter|NLRUQG]]</var> is set greater than 1, then the value of <var>LDKBMWNG</var> is rounded up to a multiple of <var> | If <var>[[NLRUQG_parameter|NLRUQG]]</var> is set greater than 1, then the value of <var>LDKBMWNG</var> is rounded up to a multiple of <var>NLRUQG</var>. <var>LDKBMWNG</var> has a minimum size of one (1). </p> | ||
<p> | <p> | ||
High values of <var>LDKBMWNG</var> might unnecessarily increase the number of writes done (measured by the DKWR statistic). Low values might cause excessive waiting for buffers (measured by the DKSWAIT statistic).</p> | High values of <var>LDKBMWNG</var> might unnecessarily increase the number of writes done (measured by the DKWR statistic). Low values might cause excessive waiting for buffers (measured by the DKSWAIT statistic).</p> | ||
<p> | <p> | ||
Refer to [[Performance monitoring and tuning#Disk buffer monitor statistics and parameters|Disk buffer monitor statistics and parameters]] for more information. </p> | Refer to [[Performance monitoring and tuning#Disk buffer monitor statistics and parameters|Disk buffer monitor statistics and parameters]] and [[Defining the runtime environment (CCAIN)#Managing ATB storage with NUMBUFG|Managing ATB storage with NUMBUFG]] for more information. </p> | ||
[[Category:System parameters]] | [[Category:System parameters]] | ||
[[Category:Parameters]] | [[Category:Parameters]] | ||
Revision as of 16:38, 5 November 2015
# of pages in DKBM-ATB anticipatory write window
Summary
- Default value
- At V7.4, either 3, or the value of LDKBMWND, if set. From V7.5 onwards the default value is set to 0.5 * NUMBUFG.
- Parameter type
- System
- Where set
- On User 0's parameter line by system manager
- Related products
- All
- Introduced
- Model 204 V7.4
Description
An anticipatory write window that starts writes for any modified buffers that enter the window
When an anticipatory write for a modified buffer completes, the buffer is immediately reusable.
If NLRUQG is set greater than 1, then the value of LDKBMWNG is rounded up to a multiple of NLRUQG. LDKBMWNG has a minimum size of one (1).
High values of LDKBMWNG might unnecessarily increase the number of writes done (measured by the DKWR statistic). Low values might cause excessive waiting for buffers (measured by the DKSWAIT statistic).
Refer to Disk buffer monitor statistics and parameters and Managing ATB storage with NUMBUFG for more information.