Index for Section 5

Alphabetical listing for S

sys_attrs_advfs(5)
NAME
  sys_attrs_advfs - advfs subsystem attributes

DESCRIPTION
  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.

  AdvfsAccessCleanupPercent
      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)

  AdvfsAccessMaxPercent
      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)

  AdvfsCacheMaxPercent
      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)

  AdvfsFavorBlockingQueue
      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.

  AdvfsMaxDevQLen
      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).

  AdvfsMaxFragGrps
      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)

  AdvfsMinFragGrps
      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)

  AdvfsPreallocAccess
      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.

  AdvfsReadyQLim
      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)

  AdvfsSyncMmapPages
      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

SEE ALSO
  sys_attrs(5)

  AdvFS Administration