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sys_attrs_advfs - advfs subsystem attributes  


This reference page lists and describes attributes for the Advanced File System (advfs) kernel subsystem. Refer to the sys_attrs(5) reference page for an introduction to the topic of kernel subsystem attributes. The percentage of access structures on the closed list that causes structures to be reclaimed from the closed list to populate the free list.

Default value: 33 (percent)
Minimum value: 5 (percent)
Maximum value: 95 (percent) The maximum percentage of the malloc pool that can be allocated for access structures.
Default value: 80 (percent)
Minimum value: 5 (percent)
Maximum value: 95 (percent) The percentage of system memory that is allocated to the AdvFS buffer cache.
Default value: 7 (percent)
Minimum value: 1 (percent)
Maximum value: 30 (percent) The value that controls the priority for moving synchronous or asynchronous I/O requests from the consolidation queue to the device queue. When the value is 1, AdvFS first flushes synchronous I/O to disk. When the value is 0 (zero), asynchronous I/O is flushed to disk, regardless of synchronous I/O.
Default value: 1
Do not modify the default setting for this attribute unless instructed to do so by Compaq Computer Corporation support personnel or by patch kit documentation. The highest number of I/O requests that can be on the AdvFS device queue before that queue is limited to synchronous requests. The AdvFS device queue accepts both asynchronous I/O requests and synchronous I/O requests. When the number of requests on the device queue exceeds the value of this attribute, only synchronous requests are accepted onto the queue.
Default value: 80 (requests)
Minimum value: 0 (requests)
Maximum value: 65536 (requests)
The default value should be appropriate for most configurations. However, you may need to modify the default value for systems with very fast or very slow devices and adapters. One guideline is to specify a value for the AdvfsMaxDevQLen attribute that is less than or equal to the average number of I/O operations that can be performed in 0.5 seconds. If you do not want to limit the size of the device queue, set the value of the AdvfsMaxDevQLen parameter to 0 (zero). The threshold number of fragment groups on the free list that starts fragment group deallocation from the list. Deallocation starts when the number of fragment groups on the free list is higher than this value.
Default value: 48 (groups)
Minimum value: 4 (groups)
Maximum value: 8192 (groups) The threshold number of fragment groups on the free list that stops fragment group deallocation from the list. Deallocation stops when the number of fragment groups on the free list is less than this value.
Default value: 16 (groups)
Minimum value: 3 (groups)
Maximum value: 8191 (groups) The number of access structures allocated on the AdvFS access structure free list at system startup. The specified number will be adjusted to conform to the value of the AdvfsAccessMaxPercent attribute.
Default value: 128 (access structures)
Minimum value: 128 (access structures)
Maximum value: 65536 (access structures)
On larger systems, specifying a value higher than the default may improve system performance by slowing the rate at which access structures are recycled, thus allowing cached file metadata to stay in main storage for a longer period of time. The number of 512-byte blocks that can be on the readylazy queue before AdvFS starts moving I/O requests to the device queue.
Default value: 16 K (blocks)
Minimum value: 0, which disables buffering on the readylazy queue
Maximum value: 32 K (blocks) A value that controls whether modified (dirty) mmapped pages are flushed to disk during a sync() system call. If the value is 1, the dirty mmapped pages are asynchronously written to disk. If the value is 0 (zero), dirty mmapped pages are not written to disk during a sync system call.
Default value: 1



AdvFS Administration




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Time: 02:43:09 GMT, October 02, 2010