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sys_attrs_cfs(5)
NAME
sys_attrs_cfs - cfs subsystem attributes
DESCRIPTION
This reference page lists and describes attributes for the cluster file
system (cfs) kernel subsystem. Refer to the sys_attrs(5) reference page for
an introduction to the topic of kernel subsystem attributes.
cnode_hash_size
Size of the hash table used to hold CFS-type vnodes (cnodes).
Set this attribute relative to the maximum number of vnodes (files)
allowed in the system. You can learn this number with the following
command:
sysconfig -q vfs max-vnodes
Supported operations: Query; Configure at boot time
Default value: If a value is not explicitly set in /etc/sysconfigtab, a
value is calculated by dividing the value of max-vnodes by 12. If the
result is even, 1 is added to it to make cnode_hash_size odd. This is
done to improve hashing performance. The result is 12 cnodes on each
hash chain (on average). This is appropriate for most cases.
Minimum value: 64
Maximum value: 16384
blkrsrv_save_percent
The percent of total space saved for block reservation. The default
value is 50MB or blkrsrv_save_percent (10) percent of the total free
space, whichever is smaller depending on the size of the domain. If
free space reaches this number, all write operations are sent to the
CFS server.
Supported operations: Query; Configure at boot time
Default value: 10
Minimum value: 5
Maximum value: 100
cfsdbg_place
Enables and disables the debugging of certain sections of CFS client
and server code.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 768
Minimum value: -9223372036854775808
Maximum value: 9223372036854775807
cfsdbg_flags
Specifies which code sections are to be debugged and how the debug
messages are output.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 0
Minimum value: -9223372036854775808
Maximum value: 9223372036854775807
cfslog_max_size
Maximum size of the CFS event trace log.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Default value: 81920
Minimum value: 8192
Maximum value: 1638400
cfslog_timestamp
If set to 1, prepend timestamp, command name and thread ID to messages
written to the CFS event trace log.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 1
Minimum value: -2147483648
Maximum value: 2147483647
cfsdbg_timeout
Number of seconds before a CFS thread that is hung waiting for a token
is timed out.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 4
Minimum value: -9223372036854775808
Maximum value: 9223372036854775807
cfsdbg_dopanic
When set to 1, panics this member on certain CFS failures. Otherwise,
the failures are logged to the CFS event trace log.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 0
Minimum value: -9223372036854775808
Maximum value: 9223372036854775807
cfsdbg_tokenlog
When set to 1, turns on CFS client and server token logging.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 3
Minimum value: -2147483648
Maximum value: 2147483647
cfsdbg_svrtok_size
Size in bytes of server token log.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 2000
Minimum value: -2147483648
Maximum value: 2147483647
cfsdbg_clitok_size
Size in bytes of client token log.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 1000
Minimum value: -2147483648
Maximum value: 2147483647
svrcfstok_max_percent
Percentage of memory that can be used by the token data structures on a
CFS server.
The svrcfstok_max_percent attribute sets an upper limit on the amount
of memory used by a CFS server to track vnode caching on clients.
Without this attribute, the only limit is the number of vnodes that can
be created at CFS client nodes. If the number of CFS clients is large
and a single cluster member serves many file systems, the server could
run out of memory and hang.
Supported operations: Query; Configure at boot time
Default value: 25
Minimum value: 5
Maximum value: 50
The default value is well suited for most situations. For more
information, see the TruCluster Server Administration manual.
no_sync_on_panic
On large configurations, the synchronization of file systems can take
considerable time, slowing failover. However, if no synchronization is
done, data not flushed to disk is lost if the data originated from an
application on the panicking member. Data originating from an
application on a remote, surviving member still exist on that member
and is rescheduled when a new server for the file system is selected.
The default, 0 (zero), allows writing buffers when the system panic.
When no_sync_on_panic is 1, the normal process of attempting to write
modified buffers back to disk when the system panics is disabled. File
corruption can result.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 0
Minimum value: 0
Maximum value: 1
cfstok_ctokhold_cache_limit
Maximum number of cached objects on the token hold freelist.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time
Default value: 1024
Minimum value: -2147483648
Maximum value: 2147483647
cfstok_ctok_req_cache_limit
Maximum number of cached objects on the token request freelist.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time
Default value: 512
Minimum value: -2147483648
Maximum value: 2147483647
cfstok_ctok_rev_cache_limit
Maximum number of cached objects on the token revoke freelist.
Do not modify the default setting for this attribute unless instructed
to do so by support personnel or by patch kit documentation.
Supported operations: Query; Configure at boot time
Default value: 256
Minimum value: -2147483648
Maximum value: 2147483647
bread
The bread attribute enables an optimization that eliminates a data copy
for NFS read requests. There should be no reason to change this
attribute from its default value.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 1
Minimum value: 0
Maximum value: 1
cfs_async_biod_threads
Controls the number of threads on the member that do read-aheads and
write-behinds for applications that perform sequential reads and
writes. The read aheads and write behinds are performed only on CFS
clients (not the CFS server).
Setting this attribute may be useful in an environment in which
sequential read and write performance of large files is important. By
default, CFS reads in 64 KB chunks. A read-ahead thread is useful when
a file has multiple 64 KB chunks that are read sequentially. Write
behind threads are useful to avoid blocking threads that are writing,
and to avoid blocking threads that are reclaiming free dirty CFS client
pages in the buffer cache.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 32
Minimum value: 0
Maximum value: 128
cfs_hsm_min_access_time
A file in a Hierarchical Storage Management (HSM) file system managed
by a UniTree application is considered by CFS to be busy if the file
was accessed in the past cfs_hsm_min_access_time seconds.
The cfs_hsm_min_access_time attribute must have the same value on every
member of the cluster. If you modify the value of the attribute, you
must do so on all members.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 300
Minimum value: 0
Maximum value: 4294967295
cfs_hsm_timeout
After an initial mount of a Hierarchical Storage Management (HSM) file
system that is to be managed by a UniTree application, and during a
failover or relocation of the CFS server for an HSM file system, the
HSM file system is unavailable until the UniTree application starts.
The cfs_hsm_timeout attribute specifies the number of seconds that CFS
holds on to an access request to the HSM managed file system. This
delay provides time for the UniTree application to start.
If cfs_hsm_timeout is set to -1 then timeout never occurs, and CFS
holds on to the access request indefinitely.
The attribute must have the same value on every member of the cluster.
If you modify the value of the attribute, you must do so on all
members.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 15
Minimum value: -1
Maximum value: 2147483647
cfsiosize
The cfsiosize attribute controls the amount of data that is processed
per pass through the client side I/O code path. The value is in
kilobytes. Making cfsiosize large results in more data being proceesed
per pass. Typically, this yields better performance.
To set the I/O size for a specific file system, overriding the effect
of cfsiosize on that file system, use the cfsmgr command to set the
FSBSIZE attribute for the file system.
See cfsmgr(8) for more information.
Supported operations: Query; Configure at boot time; Reconfigure at run
time
Default value: 65536
Minimum value: 8192
Maximum value: 131072
quota_excess_blocks
The quota_excess_blocks attribute controls the amount of dirst data
that a given user or group is allowed to cache when user or group
quotas are enabled.
The quota_excess_blocks value is expressed in units of 1024-byte blocks
and the default value is 1024, which represents one megabyte of disk
space. The value of quota_excess_blocks does not have to be the same on
all cluster members. You might use a larger quota_excess_blocks value
on cluster members on which you expect most of the data to be
generated, and accept the default value for quota_excess_blocks on
other cluster members. Use the sysconfigdb command to make changes.
Performance for a given user or group can be affected by
quota_excess_blocks. If this value is set too low, CFS will not be able
to use the cache efficiently. Setting quota_excess_blocks to less than
64K will have a severe performance impact. Conversely, setting
quota_excess_blocks too high increases the actual amount of disk space
a user or group can consume above their quota. We recommend accepting
the quota_excess_blocks default of one megabyte, or increasing it as
much as is considered practical given its effect of raising the
potential upper limit on disk block usage. When determining how to set
this value, consider that the worst-case upper boundary is determined
as follows:
(admin specified hard limit) +
(sum of "quota_excess_blocks" on each client node)
Supported operations: Query; Configure at boot time; Reconfigure at
run time.
Default value: 1024, in units of 1024-byte blocks
Minimum value: 0
Maximum value: 18446744073709551615
SEE ALSO
sys_attrs(5), cfsmgr(8)
TruCluster Server Cluster Administration
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