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6 .\" Manual: Netatalk 2.2
7 .\" Source: Netatalk 2.2
10 .TH "CNID_DBD" "8" "10 Dec 2010" "Netatalk 2.2" "Netatalk 2.2"
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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\ 'u
25 \fBcnid_dbd\fR\fB\fR\fB\fR\fB\fR \fIvolpath\fR \fIctrlfd\fR \fIclntfd\fR \fIlogconfig_string\fR
29 provides an interface for storage and retrieval of catalog node IDs (CNIDs) and related information to the
31 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\&.
42 is never started via the command line or system startup scripts but only by the
44 daemon\&. There is one instance of
46 per netatalk volume\&.
51 database library and uses transactionally protected updates\&. The
53 backend with transactions will avoid corruption of the CNID database even if the system crashes unexpectedly\&.
56 inherits the effective userid and groupid from
58 on startup, which is normally caused by
60 serving a netatalk volume to a client\&. It changes to the
62 database home directory
64 that is associated with the volume\&. If the userid inherited from
68 will change userid and groupid to the owner and group of the database home directory\&. Otherwise, it will continue to use the inherited values\&.
70 will then attempt to open the database and start serving requests using filedescriptor
71 \fIclntfd\fR\&. Subsequent instances of
73 that want to access the same volume are redirected to the running
77 via the filedescriptor
82 \fBlogconfig_string\fR
85 to configure its logging output\&.
88 can be configured to run forever or to exit after a period of inactivity\&. If
90 receives a TERM or an INT signal it will exit cleanly after flushing dirty database buffers to disk and closing
92 database environments\&. It is safe to terminate
94 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)\&.
98 database subsystem will create files named log\&.xxxxxxxxxx in the database home directory
99 \fIdbdir\fR, where xxxxxxxxxx is a monotonically increasing integer\&. These files contain ithe transactional database changes\&. They will be removed regularily, unless the
100 \fBlogfile_autoremove\fR
101 option is specified in the
103 configuration file (see below) with a value of 0 (default 1)\&.
107 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
109 configuration file to put the database onto a local disk\&.
113 reads configuration information from the file
115 in the database directory
117 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:
119 \fBlogfile_autoremove\fR
121 If set to 0, unused Berkeley DB transactional logfiles (log\&.xxxxxxxxxx in the database home directory) are not removed on startup of
123 and on a reqular basis\&. Default: 1\&.
128 Determines the size of the Berkeley DB cache in kilobytes\&. Default: 8192\&. Each
130 process grabs that much memory on top of its normal memory footprint\&. It can be used to tune database performance\&. The
134 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
135 \fBBerkeley DB Tutorial and Reference Guide\fR
137 \fBSelecting a cache size\fR
138 that gives more detailed information\&.
141 \fBflush_frequency\fR, \fBflush_interval\fR
143 \fIflush_frequency\fR
146 (Default: 1800) control how often changes to the database are checkpointed\&. Both of these operations are performed if either i) more than
147 \fIflush_frequency\fR
148 requests have been received or ii) more than
150 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\&.
155 is the maximum number of connections (filedescriptors) that can be open for
159 Default: 512\&. If this number is exceeded, one of the existing connections is closed and reused\&. The affected
161 process will transparently reconnect later, which causes slight overhead\&. On the other hand, setting this parameter too high could affect performance in
163 since all descriptors have to be checked in a
165 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
167 client process is expected to run, e\&.g\&. home directories\&.
172 is the number of seconds of inactivity before an idle
174 exits\&. Default: 600\&. Set this to 0 to disable the timeout\&.
178 Note that the first version to appear
180 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\&.
182 In order to update between older Netatalk releases using different BerkeleyDB library versions, follow this steps:
192 Stop the to be upgraded old version of Netatalk
203 Using the old BerkeleyDB utilities run
204 \fBdb_recover \-h <path to \&.AppleDB>\fR
215 Using the new BerkeleyDB utilities run
216 \fBdb_upgrade \-v \-h <path to \&.AppleDB> \-f cnid2\&.db\fR
227 Again using the new BerkeleyDB utilities run
228 \fBdb_checkpoint \-1 \-h <path to \&.AppleDB>\fR
239 Start the the new version of Netatalk