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6 .\" Manual: Netatalk 3.0
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10 .TH "CNID_DBD" "8" "01 Jan 2012" "Netatalk 3.0" "Netatalk 3.0"
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22 cnid_dbd \- implement access to CNID databases through a dedicated daemon process
24 .HP \w'\fBcnid_dbd\fR\fB\fR\fB\fR\fB\fR\fBcnid_dbd\fR\fB\fR\ 'u
25 \fBcnid_dbd\fR\fB\fR\fB\fR\fB\fR
27 \fBcnid_dbd\fR\fB\fR \-v | \-V
31 provides an interface for storage and retrieval of catalog node IDs (CNIDs) and related information to the
33 daemon\&. CNIDs are a component of Macintosh based file systems with semantics that map not easily onto Unix file systems\&. This makes separate storage in a database necessary\&.
44 is never started via the command line or system startup scripts but only by the
46 daemon\&. There is one instance of
48 per netatalk volume\&.
53 database library and uses transactionally protected updates\&. The
55 backend with transactions will avoid corruption of the CNID database even if the system crashes unexpectedly\&.
58 inherits the effective userid and groupid from
60 on startup, which is normally caused by
62 serving a netatalk volume to a client\&. It changes to the
64 database home directory
66 that is associated with the volume\&. If the userid inherited from
70 will change userid and groupid to the owner and group of the database home directory\&. Otherwise, it will continue to use the inherited values\&.
72 will then attempt to open the database and start serving requests using filedescriptor
73 \fIclntfd\fR\&. Subsequent instances of
75 that want to access the same volume are redirected to the running
79 via the filedescriptor
83 can be configured to run forever or to exit after a period of inactivity\&. If
85 receives a TERM or an INT signal it will exit cleanly after flushing dirty database buffers to disk and closing
87 database environments\&. It is safe to terminate
89 this way, it will be restarted when necessary\&. Other signals are not handled and will cause an immediate exit, possibly leaving the CNID database in an inconsistent state (no transactions) or losing recent updates during recovery (transactions)\&.
93 database subsystem will create files named log\&.xxxxxxxxxx in the database home directory
94 \fIdbdir\fR, where xxxxxxxxxx is a monotonically increasing integer\&. These files contain ithe transactional database changes\&. They will be removed regularily, unless the
95 \fBlogfile_autoremove\fR
96 option is specified in the
98 configuration file (see below) with a value of 0 (default 1)\&.
102 for databases on NFS mounted file systems\&. It makes the whole point of securing database changes properly moot\&. Use the dbdir: Option in the appropriate
104 configuration file to put the database onto a local disk\&.
109 Show version and exit\&.
114 reads configuration information from the file
116 in the database directory
118 on startup\&. If the file does not exist or a parameter is not listed, suitable default values are used\&. The format for a single parameter is the parameter name, followed by one or more spaces, followed by the parameter value, followed by a newline\&. The following parameters are currently recognized:
120 \fBlogfile_autoremove\fR
122 If set to 0, unused Berkeley DB transactional logfiles (log\&.xxxxxxxxxx in the database home directory) are not removed on startup of
124 and on a reqular basis\&. Default: 1\&.
129 Determines the size of the Berkeley DB cache in kilobytes\&. Default: 8192\&. Each
131 process grabs that much memory on top of its normal memory footprint\&. It can be used to tune database performance\&. The
135 option that comes with Berkely DB can help you determine wether you need to change this value\&. The default is pretty conservative so that a large percentage of requests should be satisfied from the cache directly\&. If memory is not a bottleneck on your system you might want to leave it at that value\&. The
136 \fBBerkeley DB Tutorial and Reference Guide\fR
138 \fBSelecting a cache size\fR
139 that gives more detailed information\&.
142 \fBflush_frequency\fR, \fBflush_interval\fR
144 \fIflush_frequency\fR
147 (Default: 1800) control how often changes to the database are checkpointed\&. Both of these operations are performed if either i) more than
148 \fIflush_frequency\fR
149 requests have been received or ii) more than
151 seconds have elapsed since the last save/checkpoint\&. Be careful to check your harddisk configuration for on disk cache settings\&. Many IDE disks just cache writes as the default behaviour, so even flushing database files to disk will not have the desired effect\&.
156 is the maximum number of connections (filedescriptors) that can be open for
160 Default: 512\&. If this number is exceeded, one of the existing connections is closed and reused\&. The affected
162 process will transparently reconnect later, which causes slight overhead\&. On the other hand, setting this parameter too high could affect performance in
164 since all descriptors have to be checked in a
166 system call, or worse, you might exceed the per process limit of open file descriptors on your system\&. It is safe to set the value to 1 on volumes where only one
168 client process is expected to run, e\&.g\&. home directories\&.
173 is the number of seconds of inactivity before an idle
175 exits\&. Default: 600\&. Set this to 0 to disable the timeout\&.
179 Note that the first version to appear
181 Netatalk 2\&.1 ie Netatalk 2\&.1\&.1, will support BerkeleyDB updates on the fly without manual intervention\&. In other words Netatalk 2\&.1 does contain code to prepare the BerkeleyDB database for upgrades and to upgrade it in case it has been prepared before\&. That means it can\'t upgrade a 2\&.0\&.x version because that one didn\'t prepare the database\&.
183 In order to update between older Netatalk releases using different BerkeleyDB library versions, follow this steps:
193 Stop the to be upgraded old version of Netatalk
204 Using the old BerkeleyDB utilities run
205 \fBdb_recover \-h <path to \&.AppleDB>\fR
216 Using the new BerkeleyDB utilities run
217 \fBdb_upgrade \-v \-h <path to \&.AppleDB> \-f cnid2\&.db\fR
228 Again using the new BerkeleyDB utilities run
229 \fBdb_checkpoint \-1 \-h <path to \&.AppleDB>\fR
240 Start the the new version of Netatalk