diff options
| author | Rainer Gerhards <rgerhards@adiscon.com> | 2007-06-15 12:39:11 +0000 |
|---|---|---|
| committer | Rainer Gerhards <rgerhards@adiscon.com> | 2007-06-15 12:39:11 +0000 |
| commit | 6ae61a905a3fb709327eb4aa9eeaff3409c4f312 (patch) | |
| tree | 1c039d0750329b192f576ccb51c4204fc275b653 /doc | |
| parent | df605232f1d71f64bd120e70d57b1fcc5fcbf29b (diff) | |
| download | rsyslog-6ae61a905a3fb709327eb4aa9eeaff3409c4f312.tar.gz rsyslog-6ae61a905a3fb709327eb4aa9eeaff3409c4f312.tar.xz rsyslog-6ae61a905a3fb709327eb4aa9eeaff3409c4f312.zip | |
removed reference to no longer existant demo server
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/rsyslog_mysql.html | 475 |
1 files changed, 236 insertions, 239 deletions
diff --git a/doc/rsyslog_mysql.html b/doc/rsyslog_mysql.html index 778b4257..d3d929f0 100644 --- a/doc/rsyslog_mysql.html +++ b/doc/rsyslog_mysql.html @@ -1,240 +1,237 @@ -<html><head>
-<title>Writing syslog Data to MySQL</title>
-<meta name="KEYWORDS" content="syslog, mysql, syslog to mysql, howto">
-</head>
-<body>
-<h1>Writing syslog messages to MySQL</h1>
- <P><small><i>Written by
- <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer
- Gerhards</a> (2005-08-02)</i></small></P>
-<h2>Abstract</h2>
-<p><i><b>In this paper, I describe how to write
-<a href="http://www.monitorware.com/en/topics/syslog/">syslog</a>
-messages to a <a href="http://www.mysql.com">MySQL</a> database.</b> Having
-syslog messages in a database is often handy, especially when you intend to set
-up a front-end for viewing them. This paper describes an approach
-with <a href="http://www.rsyslog.com/">rsyslogd</a>, an alternative enhanced
-syslog daemon natively supporting MySQL. I describe the components needed
-to be installed and how to configure them.</i></p>
-<h2>Background</h2>
-<p>In many cases, syslog data is simply written to text files. This approach has
-some advantages, most notably it is very fast and efficient. However, data
-stored in text files is not readily accessible for real-time viewing and analysis.
-To do that, the messages need to be in a database. There are various
-ways to store syslog messages in a database. For example, some have the syslogd
-write text files which are later feed via a separate script into the database.
-Others have written scripts taking the data (via a pipe) from a
-non-database-aware syslogd and store them as they appear. Some others use
-database-aware syslogds and make them write the data directly to the database.
-In this paper, I use that "direct write" approach. I think it is superior,
-because the syslogd itself knows the status of the database connection and thus
-can handle it intelligently (well ... hopefully ;)). I use rsyslogd to acomplish
-this, simply because I have initiated the rsyslog project with
-database-awareness as one goal.</p>
-<p><b>One word of caution:</b> while message storage in the database provides an
-excellent foundation for interactive analysis, it comes at a cost. Database i/o
-is considerably slower than text file i/o. As such, directly writing to
-the database makes sense only if your message volume is low enough to allow a)
-the syslogd, b) the network, and c) the database server to catch
-up with it. Some time ago, I have written a paper on
-<a href="http://www.monitorware.com/Common/en/Articles/performance-optimizing-syslog-server.php">
-optimizing syslog server performance</a>. While this paper talks about
-Window-based solutions, the ideas in it are generic enough to apply here, too.
-So it might be worth reading if you anticipate medium high to high traffic. If you
-anticipate really high traffic (or very large traffic spikes), you should
-seriously consider forgetting about direct database writes - in my opinion, such
-a situation needs either a very specialised system or a different approach (the
-text-file-to-database approach might work better for you in this case).
-</p>
-<h2>Overall System Setup</h2>
-<P>In this paper, I concentrate on the server side. If you are thinking about
-interactive syslog message review, you probably want to centralize syslog. In
-such a scenario, you have multiple machines (the so-called clients) send their
-data to a central machine (called server in this context). While I expect such a
-setup to be typical when you are interested in storing messages in the database,
-I do not describe how to set it up. This is beyond the scope of this paper. If
-you search a little, you will probably find many good descriptions on how to
-centralize syslog. If you do that, it might be a good idea to do it securely, so
-you might also be interested in my paper on <a href="rsyslog_stunnel.html">
-ssl-encrypting syslog message transfer</a>.</P>
-<P>No matter how the messages arrive at the server, their processing is always the
-same. So you can use this paper in combination with any description for
-centralized syslog reporting.</P>
-<P>As I already said, I use rsyslogd on the server. It has intrinsic support for
-talking to MySQL databases. For obvious reasons, we also need an instance of
-MySQL running. To keep us focussed, the setup of MySQL itself is also beyond the
-scope of this paper. I assume that you have successfully installed MySQL and
-also have a front-end at hand to work with it (for example,
-<a href="http://www.phpmyadmin.net/">phpMyAdmin</a>). Please make sure that this
-is installed, actually working and you have a basic understanding of how to
-handle it.</P>
-<h2>Setting up the system</h2>
-<p>You need to download and install rsyslogd first. Obtain it from the
-<a href="http://www.rsyslog.com/">rsyslog site</a>. Make sure that you disable
-stock syslogd, otherwise you will experience some difficulties.</p>
-<p>It is important to understand how rsyslogd talks to the database. In rsyslogd,
-there is the concept of "templates". Basically, a template is a string that
-includes some replacement characters, which are called "properties" in rsyslog.
-Properties are accessed via the "<a href="property_replacer.html">Property
-Replacer</a>". Simply said, you access properties by including their name
-between percent signs inside the template. For example, if the syslog message is
-"Test", the template "%msg%" would be expanded to "Test". Rsyslogd supports
-sending template text as a SQL statement to MySQL. As such, the template must be
-a valid SQL statement. There is no limit in what the statement might be, but
-there are some obvious and not so obvious choices. For example, a template "drop
-table xxx" is possible, but does not make an awful lot of sense. In practice,
-you will always use an "insert" statment inside the template.</p>
-<p>An example: if you would just like to store the msg part of the full syslog
-message, you have probably created a table "syslog" with a single column "message".
-In such a case, a good template would be "insert into syslog(message) values ('%msg%')".
-With the example above, that would be expanded to "insert into syslog(message)
-values('Test')". This expanded string is then sent to the database. It's that
-easy, no special magic. The only thing you must ensure is that your template
-expands to a proper SQL statement and that this statement matches your database
-design.</p>
-<p>Does that mean you need to create database schema yourself and also must
-fully understand rsyslogd's properties? No, that's not needed. Because we
-anticipated that folks are probably more interested in getting things going instead
-of designing them from scratch. So we have provided a default schema as well
-as build-in support for it. This schema also offers an additional
-benefit: rsyslog is part of <a href="http://www.adiscon.com/en/">Adiscon</a>'s
-<a href="http://www.monitorware.com/en/">MonitorWare product line</a> (which
-includes open source and closed source members). All of these tools share the
-same default schema and know how to operate on it. For this reason, the default
-schema is also called the "MonitorWare Schema". If you use it, you can simply
-add <a href="http://www.phplogcon.org/">phpLogCon, a GPLed syslog web interface</a>,
-to your system and have instant interactive access to your database. So there
-are some benefits in using the provided schema.</p>
-<p>The schema definition is contained in the file "createDB.sql". It comes with
-the rsyslog package. Review it to check that the database name is acceptable for
-you. Be sure to leave the table and field names unmodified, because
-otherwise you need to customize rsyslogd's default sql template, which we do not
-do
-in this paper. Then, run the script with your favourite MySQL tool. Double-check
-that the table was successfully created.</p>
-<p>Next, we need to tell rsyslogd to write data to the database. As we use
-the default schema, we do NOT need to define a template for this. We can use the
-hardcoded one (rsyslogd handles the proper template linking). So all we need to
-do is add a simple selector line to /etc/rsyslog.conf:</p>
-<blockquote>
- <p><code>*.*
- >database-server,database-name,database-userid,database-password</code></p>
-</blockquote>
-<p>In many cases, MySQL will run on the local machine. In this case, you can
-simply use "127.0.0.1" for <i>database-server</i>. This can be especially
-advisable, if you do not need to expose MySQL to any process outside of the
-local machine. In this case, you can simply bind it to 127.0.0.1, which provides
-a quite secure setup. Of course, also supports remote MySQL instances. In that
-case, use the remote server name (e.g. mysql.example.com) or IP-address. The <i>
-database-name</i> by default is "syslog". If you have modified the default, use
-your name here. <i>Database-userid</i> and <i>-password</i> are the credentials
-used to connect to the database. As they are stored in clear text in
-rsyslog.conf, that user should have only the least possible privileges. It is
-sufficient to grant it INSERT privileges to the systemevents table, only. As a
-side note, it is strongly advisable to make the rsyslog.conf file readable by
-root only - if you make it world-readable, everybody could obtain the password
-(and eventually other vital information from it). In our example, let's assume
-you have created a MySQL user named "syslogwriter" with a password of
-"topsecret" (just to say it bluntly: such a password is NOT a good idea...). If
-your MySQL database is on the local machine, your rsyslog.conf line might look
-like in this sample:</p>
-<blockquote>
- <p><code>*.*
- >127.0.0.1,syslog,syslogwriter,topsecret</code></p>
-</blockquote>
-<p>Save rsyslog.conf, restart rsyslogd - and you should see syslog messages
-being stored in the "systemevents" table!</p>
-<p>The example line stores every message to the database. Especially if you have
-a high traffic volume, you will probably limit the amount of messages being
-logged. This is easy to acomplish: the "write database" action is just a regular
-selector line. As such, you can apply normal selector-line filtering. If, for
-example, you are only interested in messages from the mail subsystem, you can
-use the following selector line:</p>
-<blockquote>
- <p><code>mail.*
- >127.0.0.1,syslog,syslogwriter,topsecret</code></p>
-</blockquote>
-<p>Review the <a href="rsyslog_conf.html">rsyslog.conf</a> documentation for
-details on selector lines and their filtering.</p>
-<p><b>You have now completed everything necessary to store syslog messages to
-the MySQL database.</b> If you would like to try out a front-end, you might want
-to look at <a href="http://www.phplogcon.org/">phpLogCon</a>, which displays
-syslog data in a browser. As of this writing, phpLogCon is not yet a powerful
-tool, but it's open source, so it might be a starting point for your own
-solution.</p>
-<h2>On Reliability...</h2>
-<p>Rsyslogd writes syslog messages directly to the database. This implies that
-the database must be available at the time of message arrival. If the database
-is offline, no space is left or something else goes wrong - rsyslogd can not
-write the database record. If rsyslogd is unable to store a message, it performs
-one retry. This is helpful if the database server was restarted. In this case,
-the previous connection was broken but a reconnect immediately succeeds. However,
-if the database is down for an extended period of time, an immediate retry does
-not help. While rsyslogd could retry until it finally succeeds, that would have
-negative impact. Syslog messages keep coming in. If rsyslogd would be busy
-retrying the database, it would not be able to process these messages.
-Ultimately, this would lead to loss of newly arrived messages.</p>
-<p>In most cases, rsyslogd is configured not only to write to the database but
-to perform other actions as well. In the always-retry scenario, that would mean
-no other actions would be carried out. As such, the design of rsyslogd is
-limited to a single retry. If that does not succeed, the current message is will
-not be written to the database and the MySQL database writer be suspended for a
-short period of time. Obviously, this leads to the loss of the current message
-as well as all messages received during the suspension period. But they are only
-lost in regard to the database, all other actions are correctly carried out.
-While not perfect, we consider this to be a better approach then the potential
-loss of all messages in all actions.</p>
-<p><b>In short: try to avoid database downtime if you do not want to experience
-message loss.</b></p>
-<p>Please note that this restriction is not rsyslogd specific. All approachs to
-real-time database storage share this problem area.</p>
-<h2>Conclusion</h2>
-<P>With minumal effort, you can use rsyslogd to write syslog messages to a MySQL
-database. Once the messages are arrived there, you can interactivley review and
-analyse them. In practice, the messages are also stored in text files for
-longer-term archival and the databases are cleared out after some time (to avoid
-becoming too slow). If you expect an extremely high syslog message volume,
-storing it in real-time to the database may outperform your database server. In
-such cases, either filter out some messages or think about alternate approaches
-involving non-real-time database writing (beyond the scope of this paper).</P>
-<P>The method outline in this paper provides an easy to setup and maintain
-solution for most use cases, especially with low and medium syslog message
-volume (or fast database servers).</P>
-<P>I have set up a site to <a href="http://demo.rsyslog.com/">demo web access to
-syslog data</a>. It is build using the steps outlined here and uses phpLogCon as
-the front-end. You might want to <a href="http://demo.rsyslog.com/">visit</a> it
-to get a glimpse of how such a beast might look.</P>
-<h3>Feedback Requested</h3>
-<P>I would appreciate feedback on this paper. If you have additional ideas,
-comments or find bugs, please
-<a href="mailto:rgerhards@adiscon.com">let me know</a>.</P>
-<h2>References and Additional Material</h2>
-<ul>
- <li><a href="http://www.rsyslog.com">www.rsyslog.com</a> - the rsyslog site</li>
- <li><a href="http://demo.rsyslog.com/">demo.rsyslog.com</a> - demo
- site for rsyslog and the phpLogCon web interface</li>
- <li>
- <a href="http://www.monitorware.com/Common/en/Articles/performance-optimizing-syslog-server.php">
- Paper on Syslog Server Optimization</a></li>
-</ul>
-<h2>Revision History</h2>
-<ul>
- <li>2005-08-02 *
- <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a> *
- initial version created</li>
- <li>2005-08-03 *
- <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a>
- * added references to demo site</li>
-</ul>
-<h2>Copyright</h2>
-<p>Copyright (c) 2005
-<a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a>
-and <a href="http://www.adiscon.com/en/">Adiscon</a>.</p>
-<p>Permission is granted to copy, distribute and/or modify this document under
-the terms of the GNU Free Documentation License, Version 1.2 or any later
-version published by the Free Software Foundation; with no Invariant Sections,
-no Front-Cover Texts, and no Back-Cover Texts. A copy of the license can be
-viewed at <a href="http://www.gnu.org/copyleft/fdl.html">
-http://www.gnu.org/copyleft/fdl.html</a>.</p>
-</body>
+<html><head> +<title>Writing syslog Data to MySQL</title> +<meta name="KEYWORDS" content="syslog, mysql, syslog to mysql, howto"> +</head> +<body> +<h1>Writing syslog messages to MySQL</h1> + <P><small><i>Written by + <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer + Gerhards</a> (2005-08-02)</i></small></P> +<h2>Abstract</h2> +<p><i><b>In this paper, I describe how to write +<a href="http://www.monitorware.com/en/topics/syslog/">syslog</a> +messages to a <a href="http://www.mysql.com">MySQL</a> database.</b> Having +syslog messages in a database is often handy, especially when you intend to set +up a front-end for viewing them. This paper describes an approach +with <a href="http://www.rsyslog.com/">rsyslogd</a>, an alternative enhanced +syslog daemon natively supporting MySQL. I describe the components needed +to be installed and how to configure them.</i></p> +<h2>Background</h2> +<p>In many cases, syslog data is simply written to text files. This approach has +some advantages, most notably it is very fast and efficient. However, data +stored in text files is not readily accessible for real-time viewing and analysis. +To do that, the messages need to be in a database. There are various +ways to store syslog messages in a database. For example, some have the syslogd +write text files which are later feed via a separate script into the database. +Others have written scripts taking the data (via a pipe) from a +non-database-aware syslogd and store them as they appear. Some others use +database-aware syslogds and make them write the data directly to the database. +In this paper, I use that "direct write" approach. I think it is superior, +because the syslogd itself knows the status of the database connection and thus +can handle it intelligently (well ... hopefully ;)). I use rsyslogd to acomplish +this, simply because I have initiated the rsyslog project with +database-awareness as one goal.</p> +<p><b>One word of caution:</b> while message storage in the database provides an +excellent foundation for interactive analysis, it comes at a cost. Database i/o +is considerably slower than text file i/o. As such, directly writing to +the database makes sense only if your message volume is low enough to allow a) +the syslogd, b) the network, and c) the database server to catch +up with it. Some time ago, I have written a paper on +<a href="http://www.monitorware.com/Common/en/Articles/performance-optimizing-syslog-server.php"> +optimizing syslog server performance</a>. While this paper talks about +Window-based solutions, the ideas in it are generic enough to apply here, too. +So it might be worth reading if you anticipate medium high to high traffic. If you +anticipate really high traffic (or very large traffic spikes), you should +seriously consider forgetting about direct database writes - in my opinion, such +a situation needs either a very specialised system or a different approach (the +text-file-to-database approach might work better for you in this case). +</p> +<h2>Overall System Setup</h2> +<P>In this paper, I concentrate on the server side. If you are thinking about +interactive syslog message review, you probably want to centralize syslog. In +such a scenario, you have multiple machines (the so-called clients) send their +data to a central machine (called server in this context). While I expect such a +setup to be typical when you are interested in storing messages in the database, +I do not describe how to set it up. This is beyond the scope of this paper. If +you search a little, you will probably find many good descriptions on how to +centralize syslog. If you do that, it might be a good idea to do it securely, so +you might also be interested in my paper on <a href="rsyslog_stunnel.html"> +ssl-encrypting syslog message transfer</a>.</P> +<P>No matter how the messages arrive at the server, their processing is always the +same. So you can use this paper in combination with any description for +centralized syslog reporting.</P> +<P>As I already said, I use rsyslogd on the server. It has intrinsic support for +talking to MySQL databases. For obvious reasons, we also need an instance of +MySQL running. To keep us focussed, the setup of MySQL itself is also beyond the +scope of this paper. I assume that you have successfully installed MySQL and +also have a front-end at hand to work with it (for example, +<a href="http://www.phpmyadmin.net/">phpMyAdmin</a>). Please make sure that this +is installed, actually working and you have a basic understanding of how to +handle it.</P> +<h2>Setting up the system</h2> +<p>You need to download and install rsyslogd first. Obtain it from the +<a href="http://www.rsyslog.com/">rsyslog site</a>. Make sure that you disable +stock syslogd, otherwise you will experience some difficulties.</p> +<p>It is important to understand how rsyslogd talks to the database. In rsyslogd, +there is the concept of "templates". Basically, a template is a string that +includes some replacement characters, which are called "properties" in rsyslog. +Properties are accessed via the "<a href="property_replacer.html">Property +Replacer</a>". Simply said, you access properties by including their name +between percent signs inside the template. For example, if the syslog message is +"Test", the template "%msg%" would be expanded to "Test". Rsyslogd supports +sending template text as a SQL statement to MySQL. As such, the template must be +a valid SQL statement. There is no limit in what the statement might be, but +there are some obvious and not so obvious choices. For example, a template "drop +table xxx" is possible, but does not make an awful lot of sense. In practice, +you will always use an "insert" statment inside the template.</p> +<p>An example: if you would just like to store the msg part of the full syslog +message, you have probably created a table "syslog" with a single column "message". +In such a case, a good template would be "insert into syslog(message) values ('%msg%')". +With the example above, that would be expanded to "insert into syslog(message) +values('Test')". This expanded string is then sent to the database. It's that +easy, no special magic. The only thing you must ensure is that your template +expands to a proper SQL statement and that this statement matches your database +design.</p> +<p>Does that mean you need to create database schema yourself and also must +fully understand rsyslogd's properties? No, that's not needed. Because we +anticipated that folks are probably more interested in getting things going instead +of designing them from scratch. So we have provided a default schema as well +as build-in support for it. This schema also offers an additional +benefit: rsyslog is part of <a href="http://www.adiscon.com/en/">Adiscon</a>'s +<a href="http://www.monitorware.com/en/">MonitorWare product line</a> (which +includes open source and closed source members). All of these tools share the +same default schema and know how to operate on it. For this reason, the default +schema is also called the "MonitorWare Schema". If you use it, you can simply +add <a href="http://www.phplogcon.org/">phpLogCon, a GPLed syslog web interface</a>, +to your system and have instant interactive access to your database. So there +are some benefits in using the provided schema.</p> +<p>The schema definition is contained in the file "createDB.sql". It comes with +the rsyslog package. Review it to check that the database name is acceptable for +you. Be sure to leave the table and field names unmodified, because +otherwise you need to customize rsyslogd's default sql template, which we do not +do +in this paper. Then, run the script with your favourite MySQL tool. Double-check +that the table was successfully created.</p> +<p>Next, we need to tell rsyslogd to write data to the database. As we use +the default schema, we do NOT need to define a template for this. We can use the +hardcoded one (rsyslogd handles the proper template linking). So all we need to +do is add a simple selector line to /etc/rsyslog.conf:</p> +<blockquote> + <p><code>*.* + >database-server,database-name,database-userid,database-password</code></p> +</blockquote> +<p>In many cases, MySQL will run on the local machine. In this case, you can +simply use "127.0.0.1" for <i>database-server</i>. This can be especially +advisable, if you do not need to expose MySQL to any process outside of the +local machine. In this case, you can simply bind it to 127.0.0.1, which provides +a quite secure setup. Of course, also supports remote MySQL instances. In that +case, use the remote server name (e.g. mysql.example.com) or IP-address. The <i> +database-name</i> by default is "syslog". If you have modified the default, use +your name here. <i>Database-userid</i> and <i>-password</i> are the credentials +used to connect to the database. As they are stored in clear text in +rsyslog.conf, that user should have only the least possible privileges. It is +sufficient to grant it INSERT privileges to the systemevents table, only. As a +side note, it is strongly advisable to make the rsyslog.conf file readable by +root only - if you make it world-readable, everybody could obtain the password +(and eventually other vital information from it). In our example, let's assume +you have created a MySQL user named "syslogwriter" with a password of +"topsecret" (just to say it bluntly: such a password is NOT a good idea...). If +your MySQL database is on the local machine, your rsyslog.conf line might look +like in this sample:</p> +<blockquote> + <p><code>*.* + >127.0.0.1,syslog,syslogwriter,topsecret</code></p> +</blockquote> +<p>Save rsyslog.conf, restart rsyslogd - and you should see syslog messages +being stored in the "systemevents" table!</p> +<p>The example line stores every message to the database. Especially if you have +a high traffic volume, you will probably limit the amount of messages being +logged. This is easy to acomplish: the "write database" action is just a regular +selector line. As such, you can apply normal selector-line filtering. If, for +example, you are only interested in messages from the mail subsystem, you can +use the following selector line:</p> +<blockquote> + <p><code>mail.* + >127.0.0.1,syslog,syslogwriter,topsecret</code></p> +</blockquote> +<p>Review the <a href="rsyslog_conf.html">rsyslog.conf</a> documentation for +details on selector lines and their filtering.</p> +<p><b>You have now completed everything necessary to store syslog messages to +the MySQL database.</b> If you would like to try out a front-end, you might want +to look at <a href="http://www.phplogcon.org/">phpLogCon</a>, which displays +syslog data in a browser. As of this writing, phpLogCon is not yet a powerful +tool, but it's open source, so it might be a starting point for your own +solution.</p> +<h2>On Reliability...</h2> +<p>Rsyslogd writes syslog messages directly to the database. This implies that +the database must be available at the time of message arrival. If the database +is offline, no space is left or something else goes wrong - rsyslogd can not +write the database record. If rsyslogd is unable to store a message, it performs +one retry. This is helpful if the database server was restarted. In this case, +the previous connection was broken but a reconnect immediately succeeds. However, +if the database is down for an extended period of time, an immediate retry does +not help. While rsyslogd could retry until it finally succeeds, that would have +negative impact. Syslog messages keep coming in. If rsyslogd would be busy +retrying the database, it would not be able to process these messages. +Ultimately, this would lead to loss of newly arrived messages.</p> +<p>In most cases, rsyslogd is configured not only to write to the database but +to perform other actions as well. In the always-retry scenario, that would mean +no other actions would be carried out. As such, the design of rsyslogd is +limited to a single retry. If that does not succeed, the current message is will +not be written to the database and the MySQL database writer be suspended for a +short period of time. Obviously, this leads to the loss of the current message +as well as all messages received during the suspension period. But they are only +lost in regard to the database, all other actions are correctly carried out. +While not perfect, we consider this to be a better approach then the potential +loss of all messages in all actions.</p> +<p><b>In short: try to avoid database downtime if you do not want to experience +message loss.</b></p> +<p>Please note that this restriction is not rsyslogd specific. All approachs to +real-time database storage share this problem area.</p> +<h2>Conclusion</h2> +<P>With minumal effort, you can use rsyslogd to write syslog messages to a MySQL +database. Once the messages are arrived there, you can interactivley review and +analyse them. In practice, the messages are also stored in text files for +longer-term archival and the databases are cleared out after some time (to avoid +becoming too slow). If you expect an extremely high syslog message volume, +storing it in real-time to the database may outperform your database server. In +such cases, either filter out some messages or think about alternate approaches +involving non-real-time database writing (beyond the scope of this paper).</P> +<P>The method outlined in this paper provides an easy to setup and maintain +solution for most use cases, especially with low and medium syslog message +volume (or fast database servers).</P> +<h3>Feedback Requested</h3> +<P>I would appreciate feedback on this paper. If you have additional ideas, +comments or find bugs, please +<a href="mailto:rgerhards@adiscon.com">let me know</a>.</P> +<h2>References and Additional Material</h2> +<ul> + <li><a href="http://www.rsyslog.com">www.rsyslog.com</a> - the rsyslog site</li> + <li> + <a href="http://www.monitorware.com/Common/en/Articles/performance-optimizing-syslog-server.php"> + Paper on Syslog Server Optimization</a></li> +</ul> +<h2>Revision History</h2> +<ul> + <li>2005-08-02 * + <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a> * + initial version created</li> + <li>2005-08-03 * + <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a> + * added references to demo site</li> + <li>2007-06-13 * + <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a> + * removed demo site - was torn down because too expensive for usage count</li> +</ul> +<h2>Copyright</h2> +<p>Copyright (c) 2005-2007 +<a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a> +and <a href="http://www.adiscon.com/en/">Adiscon</a>.</p> +<p>Permission is granted to copy, distribute and/or modify this document under +the terms of the GNU Free Documentation License, Version 1.2 or any later +version published by the Free Software Foundation; with no Invariant Sections, +no Front-Cover Texts, and no Back-Cover Texts. A copy of the license can be +viewed at <a href="http://www.gnu.org/copyleft/fdl.html"> +http://www.gnu.org/copyleft/fdl.html</a>.</p> +</body> </html>
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