pgsql/doc/postgresql/html/app-pgverifybackup.html

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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>pg_verifybackup</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="app-pgrestore.html" title="pg_restore" /><link rel="next" href="app-psql.html" title="psql" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center"><span class="application">pg_verifybackup</span></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="app-pgrestore.html" title="pg_restore">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="reference-client.html" title="PostgreSQL Client Applications">Up</a></td><th width="60%" align="center">PostgreSQL Client Applications</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="app-psql.html" title="psql">Next</a></td></tr></table><hr /></div><div class="refentry" id="APP-PGVERIFYBACKUP"><div class="titlepage"></div><a id="id-1.9.4.19.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle"><span class="application">pg_verifybackup</span></span></h2><p>pg_verifybackup — verify the integrity of a base backup of a
  <span class="productname">PostgreSQL</span> cluster</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p id="id-1.9.4.19.4.1"><code class="command">pg_verifybackup</code> [<em class="replaceable"><code>option</code></em>...]</p></div></div><div class="refsect1" id="id-1.9.4.19.5"><h2>Description</h2><p>
   <span class="application">pg_verifybackup</span> is used to check the
   integrity of a database cluster backup taken using
   <code class="command">pg_basebackup</code> against a
   <code class="literal">backup_manifest</code> generated by the server at the time
   of the backup.  The backup must be stored in the "plain"
   format; a "tar" format backup can be checked after extracting it.
  </p><p>
   It is important to note that the validation which is performed by
   <span class="application">pg_verifybackup</span> does not and cannot include
   every check which will be performed by a running server when attempting
   to make use of the backup. Even if you use this tool, you should still
   perform test restores and verify that the resulting databases work as
   expected and that they appear to contain the correct data. However,
   <span class="application">pg_verifybackup</span> can detect many problems
   that commonly occur due to storage problems or user error.
  </p><p>
   Backup verification proceeds in four stages. First,
   <code class="literal">pg_verifybackup</code> reads the
   <code class="literal">backup_manifest</code> file. If that file
   does not exist, cannot be read, is malformed, or fails verification
   against its own internal checksum, <code class="literal">pg_verifybackup</code>
   will terminate with a fatal error.
  </p><p>
   Second, <code class="literal">pg_verifybackup</code> will attempt to verify that
   the data files currently stored on disk are exactly the same as the data
   files which the server intended to send, with some exceptions that are
   described below. Extra and missing files will be detected, with a few
   exceptions.  This step will ignore the presence or absence of, or any
   modifications to, <code class="literal">postgresql.auto.conf</code>,
   <code class="literal">standby.signal</code>, and <code class="literal">recovery.signal</code>,
   because it is expected that these files may have been created or modified
   as part of the process of taking the backup. It also won't complain about
   a <code class="literal">backup_manifest</code> file in the target directory or
   about anything inside <code class="literal">pg_wal</code>, even though these
   files won't be listed in the backup manifest. Only files are checked;
   the presence or absence of directories is not verified, except
   indirectly: if a directory is missing, any files it should have contained
   will necessarily also be missing.
  </p><p>
   Next, <code class="literal">pg_verifybackup</code> will checksum all the files,
   compare the checksums against the values in the manifest, and emit errors
   for any files for which the computed checksum does not match the
   checksum stored in the manifest. This step is not performed for any files
   which produced errors in the previous step, since they are already known
   to have problems. Files which were ignored in the previous step are also
   ignored in this step.
  </p><p>
   Finally, <code class="literal">pg_verifybackup</code> will use the manifest to
   verify that the write-ahead log records which will be needed to recover
   the backup are present and that they can be read and parsed. The
   <code class="literal">backup_manifest</code> contains information about which
   write-ahead log records will be needed, and
   <code class="literal">pg_verifybackup</code> will use that information to
   invoke <code class="literal">pg_waldump</code> to parse those write-ahead log
   records. The <code class="literal">--quiet</code> flag will be used, so that
   <code class="literal">pg_waldump</code> will only report errors, without producing
   any other output. While this level of verification is sufficient to
   detect obvious problems such as a missing file or one whose internal
   checksums do not match, they aren't extensive enough to detect every
   possible problem that might occur when attempting to recover. For
   instance, a server bug that produces write-ahead log records that have
   the correct checksums but specify nonsensical actions can't be detected
   by this method.
  </p><p>
   Note that if extra WAL files which are not required to recover the backup
   are present, they will not be checked by this tool, although
   a separate invocation of <code class="literal">pg_waldump</code> could be used for
   that purpose. Also note that WAL verification is version-specific: you
   must use the version of <code class="literal">pg_verifybackup</code>, and thus of
   <code class="literal">pg_waldump</code>, which pertains to the backup being checked.
   In contrast, the data file integrity checks should work with any version
   of the server that generates a <code class="literal">backup_manifest</code> file.
  </p></div><div class="refsect1" id="id-1.9.4.19.6"><h2>Options</h2><p>
    <span class="application">pg_verifybackup</span> accepts the following
    command-line arguments:

    </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">-e</code><br /></span><span class="term"><code class="option">--exit-on-error</code></span></dt><dd><p>
        Exit as soon as a problem with the backup is detected. If this option
        is not specified, <code class="literal">pg_verifybackup</code> will continue
        checking the backup even after a problem has been detected, and will
        report all problems detected as errors.
       </p></dd><dt><span class="term"><code class="option">-i <em class="replaceable"><code>path</code></em></code><br /></span><span class="term"><code class="option">--ignore=<em class="replaceable"><code>path</code></em></code></span></dt><dd><p>
        Ignore the specified file or directory, which should be expressed
        as a relative path name, when comparing the list of data files
        actually present in the backup to those listed in the
        <code class="literal">backup_manifest</code> file.  If a directory is
        specified, this option affects the entire subtree rooted at that
        location. Complaints about extra files, missing files, file size
        differences, or checksum mismatches will be suppressed if the
        relative path name matches the specified path name. This option
        can be specified multiple times.
       </p></dd><dt><span class="term"><code class="option">-m <em class="replaceable"><code>path</code></em></code><br /></span><span class="term"><code class="option">--manifest-path=<em class="replaceable"><code>path</code></em></code></span></dt><dd><p>
        Use the manifest file at the specified path, rather than one located
        in the root of the backup directory.
       </p></dd><dt><span class="term"><code class="option">-n</code><br /></span><span class="term"><code class="option">--no-parse-wal</code></span></dt><dd><p>
        Don't attempt to parse write-ahead log data that will be needed
        to recover from this backup.
       </p></dd><dt><span class="term"><code class="option">-P</code><br /></span><span class="term"><code class="option">--progress</code></span></dt><dd><p>
        Enable progress reporting. Turning this on will deliver a progress
        report while verifying checksums.
       </p><p>
        This option cannot be used together with the option
        <code class="option">--quiet</code>.
       </p></dd><dt><span class="term"><code class="option">-q</code><br /></span><span class="term"><code class="option">--quiet</code></span></dt><dd><p>
        Don't print anything when a backup is successfully verified.
       </p></dd><dt><span class="term"><code class="option">-s</code><br /></span><span class="term"><code class="option">--skip-checksums</code></span></dt><dd><p>
        Do not verify data file checksums. The presence or absence of
        files and the sizes of those files will still be checked. This is
        much faster, because the files themselves do not need to be read.
       </p></dd><dt><span class="term"><code class="option">-w <em class="replaceable"><code>path</code></em></code><br /></span><span class="term"><code class="option">--wal-directory=<em class="replaceable"><code>path</code></em></code></span></dt><dd><p>
        Try to parse WAL files stored in the specified directory, rather than
        in <code class="literal">pg_wal</code>. This may be useful if the backup is
        stored in a separate location from the WAL archive.
       </p></dd></dl></div><p>
   </p><p>
    Other options are also available:

    </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">-V</code><br /></span><span class="term"><code class="option">--version</code></span></dt><dd><p>
       Print the <span class="application">pg_verifybackup</span> version and exit.
       </p></dd><dt><span class="term"><code class="option">-?</code><br /></span><span class="term"><code class="option">--help</code></span></dt><dd><p>
       Show help about <span class="application">pg_verifybackup</span> command
       line arguments, and exit.
       </p></dd></dl></div><p>
   </p></div><div class="refsect1" id="id-1.9.4.19.7"><h2>Examples</h2><p>
   To create a base backup of the server at <code class="literal">mydbserver</code> and
   verify the integrity of the backup:
</p><pre class="screen">
<code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -h mydbserver -D /usr/local/pgsql/data</code></strong>
<code class="prompt">$</code> <strong class="userinput"><code>pg_verifybackup /usr/local/pgsql/data</code></strong>
</pre><p>
  </p><p>
   To create a base backup of the server at <code class="literal">mydbserver</code>, move
   the manifest somewhere outside the backup directory, and verify the
   backup:
</p><pre class="screen">
<code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -h mydbserver -D /usr/local/pgsql/backup1234</code></strong>
<code class="prompt">$</code> <strong class="userinput"><code>mv /usr/local/pgsql/backup1234/backup_manifest /my/secure/location/backup_manifest.1234</code></strong>
<code class="prompt">$</code> <strong class="userinput"><code>pg_verifybackup -m /my/secure/location/backup_manifest.1234 /usr/local/pgsql/backup1234</code></strong>
</pre><p>
  </p><p>
   To verify a backup while ignoring a file that was added manually to the
   backup directory, and also skipping checksum verification:
</p><pre class="screen">
<code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -h mydbserver -D /usr/local/pgsql/data</code></strong>
<code class="prompt">$</code> <strong class="userinput"><code>edit /usr/local/pgsql/data/note.to.self</code></strong>
<code class="prompt">$</code> <strong class="userinput"><code>pg_verifybackup --ignore=note.to.self --skip-checksums /usr/local/pgsql/data</code></strong>
</pre></div><div class="refsect1" id="id-1.9.4.19.8"><h2>See Also</h2><span class="simplelist"><a class="xref" href="app-pgbasebackup.html" title="pg_basebackup"><span class="refentrytitle"><span class="application">pg_basebackup</span></span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="app-pgrestore.html" title="pg_restore">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="reference-client.html" title="PostgreSQL Client Applications">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="app-psql.html" title="psql">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="application">pg_restore</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="40%" align="right" valign="top"> <span class="application">psql</span></td></tr></table></div></body></html>