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Rename pg_validatebackup to pg_verifybackup.

Browse Source 
Also, use "verify" rather than "validate" to refer to the process
being undertaken here. Per discussion, that is a more appropriate
term.

Discussion: https://www.postgresql.org/message-id/172c9d9b-1d0a-1b94-1456-376b1e017322@2ndquadrant.com
Discussion: http://postgr.es/m/CA+TgmobLgMh6p8FmLbj_rv9Uhd7tPrLnAyLgGd2SoSj=qD-bVg@mail.gmail.com
This commit is contained in:
Robert Haas
2020-04-12 11:26:05 -04:00
parent 26640c4071
commit dbc60c5593
18 changed files with 142 additions and 142 deletions
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doc/src/sgml/ref/pg_verifybackup.sgml Normal file
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<!--
doc/src/sgml/ref/pg_verifybackup.sgml
PostgreSQL documentation
-->
<refentry id="app-pgverifybackup">
<indexterm zone="app-pgverifybackup">
<primary>pg_verifybackup</primary>
</indexterm>
<refmeta>
<refentrytitle>pg_verifybackup</refentrytitle>
<manvolnum>1</manvolnum>
<refmiscinfo>Application</refmiscinfo>
</refmeta>
<refnamediv>
<refname>pg_verifybackup</refname>
<refpurpose>verify the integrity of a base backup of a
<productname>PostgreSQL</productname> cluster</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>pg_verifybackup</command>
<arg rep="repeat"><replaceable>option</replaceable></arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>
Description
</title>
<para>
<application>pg_verifybackup</application> is used to check the
integrity of a database cluster backup taken using
<command>pg_basebackup</command> against a
<literal>backup_manifest</literal> 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.
</para>
<para>
It is important to note that that the validation which is performed by
<application>pg_verifybackup</application> does not and can not 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,
<application>pg_verifybackup</application> can detect many problems
that commonly occur due to storage problems or user error.
</para>
<para>
Backup verification proceeds in four stages. First,
<literal>pg_verifybackup</literal> reads the
<literal>backup_manifest</literal> file. If that file
does not exist, cannot be read, is malformed, or fails verification
against its own internal checksum, <literal>pg_verifybackup</literal>
will terminate with a fatal error.
</para>
<para>
Second, <literal>pg_verifybackup</literal> 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, <literal>postgresql.auto.conf</literal>,
<literal>standby.signal</literal>, and <literal>recovery.signal</literal>,
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 <literal>backup_manifest</literal> file in the target directory or
about anything inside <literal>pg_wal</literal>, 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.
</para>
<para>
Next, <literal>pg_verifybackup</literal> 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. Also, files which were ignored in the previous step are
also ignored in this step.
</para>
<para>
Finally, <literal>pg_verifybackup</literal> 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
<literal>backup_manifest</literal> contains information about which
write-ahead log records will be needed, and
<literal>pg_verifybackup</literal> will use that information to
invoke <literal>pg_waldump</literal> to parse those write-ahed log
records. The <literal>--quiet</literal> flag will be used, so that
<literal>pg_waldump</literal> 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.
</para>
<para>
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 <literal>pg_waldump</literal> could be used for
that purpose. Also note that WAL verification is version-specific: you
must use the version of <literal>pg_verifybackup</literal>, and thus of
<literal>pg_waldump</literal>, 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 <literal>backup_manifest</literal> file.
</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>
The following command-line options control the behavior.
<variablelist>
<varlistentry>
<term><option>-e</option></term>
<term><option>--exit-on-error</option></term>
<listitem>
<para>
Exit as soon as a problem with the backup is detected. If this option
is not specified, <literal>pg_validatebackup</literal> will continue
checking the backup even after a problem has been detected, and will
report all problems detected as errors.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-i <replaceable class="parameter">path</replaceable></option></term>
<term><option>--ignore=<replaceable class="parameter">path</replaceable></option></term>
<listitem>
<para>
Ignore the specified file or directory, which should be expressed
as a relative pathname, when comparing the list of data files
actually present in the backup to those listed in the
<literal>backup_manifest</literal> 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 pathname matches the specified pathname. This option
can be specified multiple times.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-m <replaceable class="parameter">path</replaceable></option></term>
<term><option>--manifest-path=<replaceable class="parameter">path</replaceable></option></term>
<listitem>
<para>
Use the manifest file at the specified path, rather than one located
in the root of the backup directory.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-n</option></term>
<term><option>--no-parse-wal</option></term>
<listitem>
<para>
Don't attempt to parse write-ahead log data that will be needed
to recover from this backup.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-q</option></term>
<term><option>--quiet</option></term>
<listitem>
<para>
Don't print anything when a backup is successfully verified.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-s</option></term>
<term><option>--skip-checksums</option></term>
<listitem>
<para>
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.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-w <replaceable class="parameter">path</replaceable></option></term>
<term><option>--wal-directory=<replaceable class="parameter">path</replaceable></option></term>
<listitem>
<para>
Try to parse WAL files stored in the specified directory, rather than
in <literal>pg_wal</literal>. This may be useful if the backup is
stored in a separate location from the WAL archive.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
<para>
Other options are also available:
<variablelist>
<varlistentry>
<term><option>-V</option></term>
<term><option>--version</option></term>
<listitem>
<para>
Print the <application>pg_verifybackup</application> version and exit.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-?</option></term>
<term><option>--help</option></term>
<listitem>
<para>
Show help about <application>pg_verifybackup</application> command
line arguments, and exit.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
To create a base backup of the server at <literal>mydbserver</literal> and
verify the integrity of the backup:
<screen>
<prompt>$</prompt> <userinput>pg_basebackup -h mydbserver -D /usr/local/pgsql/data</userinput>
<prompt>$</prompt> <userinput>pg_verifybackup /usr/local/pgsql/data</userinput>
</screen>
</para>
<para>
To create a base backup of the server at <literal>mydbserver</literal>, move
the manifest somewhere outside the backup directory, and verify the
backup:
<screen>
<prompt>$</prompt> <userinput>pg_basebackup -h mydbserver -D /usr/local/pgsql/backup1234</userinput>
<prompt>$</prompt> <userinput>mv /usr/local/pgsql/backup1234/backup_manifest /my/secure/location/backup_manifest.1234</userinput>
<prompt>$</prompt> <userinput>pg_verifybackup -m /my/secure/location/backup_manifest.1234 /usr/local/pgsql/backup1234</userinput>
</screen>
</para>
<para>
To verify a backup while ignoring a file that was added manually to the
backup directory, and also skipping checksum verification:
<screen>
<prompt>$</prompt> <userinput>pg_basebackup -h mydbserver -D /usr/local/pgsql/data</userinput>
<prompt>$</prompt> <userinput>edit /usr/local/pgsql/data/note.to.self</userinput>
<prompt>$</prompt> <userinput>pg_verifybackup --ignore=note.to.self --skip-checksums /usr/local/pgsql/data</userinput>
</screen>
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="app-pgbasebackup"/></member>
</simplelist>
</refsect1>
</refentry>