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167 | 167 | <productname>PostgreSQL</> periodically writes full page images to
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168 | 168 | permanent WAL storage <emphasis>before</> modifying the actual page on
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169 | 169 | disk. By doing this, during crash recovery <productname>PostgreSQL</> can
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170 |
| - restore partially-written pages from WAL. If you have a battery-backed disk |
171 |
| - controller or file-system software that prevents partial page writes |
172 |
| - (e.g., ZFS), you can safely turn off this page imaging by turning off the |
173 |
| - <xref linkend="guc-full-page-writes"> parameter. |
| 170 | + restore partially-written pages from WAL. If you have file-system software |
| 171 | + that prevents partial page writes (e.g., ZFS), you can turn off |
| 172 | + this page imaging by turning off the <xref |
| 173 | + linkend="guc-full-page-writes"> parameter. Battery-Backed Unit |
| 174 | + (BBU) disk controllers do not prevent partial page writes unless |
| 175 | + they guarantee that data is written to the BBU as full (8kB) pages. |
174 | 176 | </para>
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175 | 177 | </sect1>
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176 | 178 |
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