Content-type: text/html
Man page of sys_attrs_advfs
sys_attrs_advfs
Section: File Formats (5)
Index
Return to Main Contents
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.
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
SEE ALSO
sys_attrs(5)
AdvFS Administration
Index
- NAME
-
- DESCRIPTION
-
- SEE ALSO
-
This document was created by
man2html,
using the manual pages.
Time: 02:43:09 GMT, October 02, 2010