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2 | | -$Header: /cvsroot/pgsql/doc/src/sgml/diskusage.sgml,v 1.5 2002/09/21 18:32:52 petere Exp $ |
| 2 | +$Header: /cvsroot/pgsql/doc/src/sgml/diskusage.sgml,v 1.6 2002/10/16 22:06:33 petere Exp $ |
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4 | 4 |
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5 | 5 | <chapter id="diskusage"> |
6 | 6 | <title>Monitoring Disk Usage</title> |
7 | 7 |
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| 8 | + <para> |
| 9 | + This chapter discusses how to monitor the disk usage of a PostgreSQL |
| 10 | + database system. In the current release, the database administrator |
| 11 | + does not have much control over the on-disk storage layout, so this |
| 12 | + chapter is mostly informative and can give you some ideas how to |
| 13 | + manage the disk usage with operating system tools. |
| 14 | + </para> |
| 15 | + |
8 | 16 | <sect1 id="disk-usage"> |
9 | | - <title>Monitoring Disk Usage</Title> |
| 17 | + <title>Determining Disk Usage</Title> |
10 | 18 |
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11 | 19 | <indexterm zone="disk-usage"> |
12 | 20 | <primary>disk usage</primary> |
@@ -96,6 +104,40 @@ play-# ORDER BY relpages DESC; |
96 | 104 | shows disk usage for each database. |
97 | 105 | </para> |
98 | 106 | </sect1> |
| 107 | + |
| 108 | + <sect1 id="disk-full"> |
| 109 | + <title>Disk Full Failure</title> |
| 110 | + |
| 111 | + <para> |
| 112 | + The most important disk monitoring task of a database administrator |
| 113 | + is to make sure the disk doesn't grow full. A filled data disk may |
| 114 | + result in subsequent corruption of database indexes, but not of the |
| 115 | + fundamental data tables. If the WAL files are on the same disk (as |
| 116 | + is the case for a default configuration) then a filled disk during |
| 117 | + database initialization may result in corrupted or incomplete WAL |
| 118 | + files. This failure condition is detected and the database server |
| 119 | + will refuse to start up. |
| 120 | + </para> |
| 121 | + |
| 122 | + <para> |
| 123 | + If you cannot free up additional space on the disk by deleting |
| 124 | + other things you can move some of the database files to other file |
| 125 | + systems and create a symlink from the original location. But |
| 126 | + note that <application>pg_dump</> cannot save the location layout |
| 127 | + information of such a setup; a restore would put everything back in |
| 128 | + one place. To avoid running out of disk space, you can place the |
| 129 | + WAL files or individual databases in other locations while creating |
| 130 | + them. See the <application>initdb</> documentation and <xref |
| 131 | + linkend="manage-ag-alternate-locs"> for more information. |
| 132 | + </para> |
| 133 | + |
| 134 | + <tip> |
| 135 | + <para> |
| 136 | + Some file systems perform badly when they are almost full, so do |
| 137 | + not wait until the disk is full to take action. |
| 138 | + </para> |
| 139 | + </tip> |
| 140 | + </sect1> |
99 | 141 | </chapter> |
100 | 142 |
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