XBSSNAPSHOT(1) CoreXBS Tools XBSSNAPSHOT(1)NAME
xbssnapshot - CoreXBS snapshot utility
SYNOPSIS
xbssnapshot fetch [--[no]live] [--age hours] [--[no]xpc] train_name
xbssnapshot authcheck [--timeout seconds] train_name
DESCRIPTION
In the 1st form, xbssnapshot is used to obtain a snapshot of Cortex for train_name. A cache of snapshots is maintained in a directory,
which may or may not be used in addition to consulting the Cortex servers depending on command line OPTIONS specified. If successful, a
file URL of a suitable snasphot is printed to STDOUT. On failure, a description of the failure is printed to STDERR.
In the 2nd form, xbssnapshot is used to check connectivity to the Cortex servers for train_name and determine if AppleConnect (Single
Sign-On) credentials will be required to obtain a snapshot. If the Cortex server can be reached, YES is printed to STDOUT if SSO authenti-
cation is required and NO is printed if not. On failure (including not being able to reach the Cortex servers), a description of the fail-
ure is printed to STDERR.
OPTIONS --live Force xbssnapshot to bypass the snapshot cache directory and fetch data from Cortex.
--nolive
Force xbssnapshot to not fetch data from Cortex and only use the snapshot cache directory.
--age hours
When considering if a snapshot found in the snapshot cache directory is "new enough", only accept snapshots that are less than hours
old.
--xpc Use XPC service when fetching data from Cortex. This is the default.
--noxpc
Bypass XPC service when fetching data from Cortex.
--timeout seconds
When performing connectivity test with Cortex server(s), how long to wait before assuming no connectivity to a given Cortex server.
RETURN VALUES
Returns 0 on success, and non-zero on failure.
ENVIRONMENT
CTXHost
May be set to the hostname of a specific Cortex server. This is mainly only useful to the developers.
CTXPort
May be set to specific port to connect to CTXHost on (does nothing unless CTXHost is also set). This is mainly only useful to the
developers.
FILES
/Library/Caches/com.apple.bni.cortexsnapshot
Directory where snapshots are cached.
/var/log/system.log
CoreXBS framework and XPC services log here. grep CoreXBS /var/log/system.log may show additional information above and beyond what
xbssnapshot prints on it's own.
BUGS
If you encounter issues with xbssnapshot, please file a Radar. Component is "CBL - CoreXBS|X". Please include the following information, if
possible:
1. Output of xbssnapshot, including command line it was invoked with.
2. Output of ls -lh /Library/Caches/com.apple.bni.cortexsnapshot
3. Output of grep CoreXBS /var/log/system.log
4. If a snapshot was fetched, a copy of the snapshot.
AUTHOR
Problems with xbssnapshot should be addressed via Radar (see BUGS). For discussion and advice from other users please subscribe to
xbs-help@group.apple.com. The maintainers of xbssnapshot are cbt@group.apple.com. Suggestions and comments are always welcome!
Core Build Technologies March 2013 XBSSNAPSHOT(1)
Check Out this Related Man Page
vxcached(1M)vxcached(1M)NAME
vxcached - resize cache volumes when required
SYNOPSIS
/etc/vx/bin/vxcached [-v] [mail-address ...]
DESCRIPTION
The Veritas Volume Manager cache daemon, vxcached, is invoked by the VxVM kernel to monitor the cache objects that are used by space-opti-
mized snapshots. When usage of a cache volume by space-optimized snapshots reaches the high watermark level that has been set for the
cache, vxcached automatically grows the cache volume if this is required and configured.
The -v option enables the daemon in verbose mode. If no mail addresses are given as arguments, mail is sent to root.
If the autogrow feature has been enabled on a cache object, the values of the highwatermark, autogrowby and maxautogrow attributes for the
cache object determine the behavior of vxcached:
o When cache usage reaches the high watermark value, highwatermark, (default value is 90 percent), and the new required cache size would
not exceed the value of maxautogrow (default value is twice the size of the cache volume in blocks), vxcached grows the size of the
cache volume by the value of autogrowby (default value is 20% of the size of the cache volume in blocks).
o When cache usage reaches the high watermark value, and the new required cache size would exceed the value of maxautogrow, vxcached
deletes the oldest snapshot in the cache. If there are several snapshots with the same age, the largest of these is deleted.
If the autogrow feature has been disabled on a cache object:
o When cache usage reaches the high watermark value, vxcached deletes the oldest snapshot in the cache. If there are several snapshots
with the same age, the largest of these is deleted. If there is only a single snapshot, the snapshot is detached and marked as invalid.
The values of the highwatermark, autogrowby and maxautogrow attributes can be set when a cache object is created using vxmake. If neces-
sary, you can use the vxcache set command to change the values of these attributes for an existing cache.
NOTES
The vxcached daemon is started automatically if a license for the FastResync feature is already present on the system. If you add such a
license while VxVM is running, you can either start vxcached manually, or shut down and reboot the system.
Killing the vxcached process stops it from removing snapshots. The daemon can be prevented from being started by commenting out its entry
in the startup script, /sbin/init.d/vxvm-recover.
The vxcached daemon does not remove snapshots that are currently open, and it does not remove the last or only snapshot in the cache.
If the cache space becomes exhausted, the snapshot is detached. If this happens, the snapshot is unrecoverable and must be removed manu-
ally. Enabling the autogrow feature on the cache helps to avoid this situation occurring. However, for very small caches (of the order of
a few megabytes), it is possible for the cache to become exhausted before the system has time to respond and grow the cache. In such
cases, either increase the size of the cache manually, or reduce the value of highwatermark.
You can use the maxautogrow attribute to limit the maximum size to which a cache can grow. To estimate this size, consider how much the
contents of each source volume are likely to change between snapshot refreshes, and allow some additional space for contingency.
SEE ALSO vxcache(1M), vxintro(1M), vxmake(1M), vxsnap(1M)VxVM 5.0.31.1 24 Mar 2008 vxcached(1M)