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1 | 1 | <!-- |
2 | | -$PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.73 2005/10/22 22:09:49 tgl Exp $ |
| 2 | +$PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.74 2005/10/26 20:42:35 tgl Exp $ |
3 | 3 | --> |
4 | 4 | <chapter id="backup"> |
5 | 5 | <title>Backup and Restore</title> |
@@ -677,12 +677,20 @@ SELECT pg_stop_backup(); |
677 | 677 | </para> |
678 | 678 |
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679 | 679 | <para> |
680 | | - Some versions of GNU <application>tar</> consider it an error if a file |
681 | | - is changed while <application>tar</> is copying it. This case is normal, |
682 | | - and not an error, when taking a base backup of an active database. |
683 | | - Since ignoring all errors from <application>tar</> would be unwise, |
684 | | - you should either manually inspect <application>tar</>'s messages or |
685 | | - else use a different backup tool that does not complain about this case. |
| 680 | + Some backup tools that you might wish to use emit warnings or errors |
| 681 | + if the files they are trying to copy change while the copy proceeds. |
| 682 | + This situation is normal, and not an error, when taking a base backup of |
| 683 | + an active database; so you need to ensure that you can distinguish |
| 684 | + complaints of this sort from real errors. For example, some versions |
| 685 | + of <application>rsync</> return a separate exit code for <quote>vanished |
| 686 | + source files</>, and you can write a driver script to accept this exit |
| 687 | + code as a non-error case. Also, |
| 688 | + some versions of GNU <application>tar</> consider it an error if a file |
| 689 | + is changed while <application>tar</> is copying it. There does not seem |
| 690 | + to be any very convenient way to distinguish this error from other types |
| 691 | + of errors, other than manual inspection of <application>tar</>'s messages. |
| 692 | + GNU <application>tar</> is therefore not the best tool for making base |
| 693 | + backups. |
686 | 694 | </para> |
687 | 695 |
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688 | 696 | <para> |
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