<html>#2938: use SWMR mode for HDF5 output in CarpetIOHDF5
<table style='border-spacing: 1ex 0pt; '>
<tr><td style='text-align:right'> Reporter:</td><td>Roland Haas</td></tr>
<tr><td style='text-align:right'> Status:</td><td>new</td></tr>
<tr><td style='text-align:right'>Milestone:</td><td></td></tr>
<tr><td style='text-align:right'> Version:</td><td></td></tr>
<tr><td style='text-align:right'> Type:</td><td>enhancement</td></tr>
<tr><td style='text-align:right'> Priority:</td><td>minor</td></tr>
<tr><td style='text-align:right'>Component:</td><td>Carpet</td></tr>
</table>
<p>New versions of HDF5 support a single-writer, multiple reader (SWMR) mode that keeps files intact while appending to existing datasets. </p>
<p>This can be helpful for CarpetIOHDF5 since it reduces the window in time during which files would be corrupted if Cactus is terminated while writing to a file. A high-level description of the functionality is found on:</p>
<p><a href="https://support.hdfgroup.org/documentation/hdf5/latest/_s_w_m_r_t_n.html" rel="nofollow" class="ap-connect-link">https://support.hdfgroup.org/documentation/hdf5/latest/_s_w_m_r_t_n.html</a></p>
<p>Unfortunately, even for the reader, the functionality is not fully transparent it seems (namely the reader must pass flags to <code>H5Fopen</code>), so this may require a "fix-files" step to make partially written files readable with standard utilities (eg VisIt). But at least the files themselves would be mostly intact.</p>
<p>--<br/>
Ticket URL: <a href='https://bitbucket.org/einsteintoolkit/tickets/issues/2938/use-swmr-mode-for-hdf5-output-in'>https://bitbucket.org/einsteintoolkit/tickets/issues/2938/use-swmr-mode-for-hdf5-output-in</a></p>
</html>