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Stable pagesStable pagesPosted May 13, 2011 5:27 UTC (Fri) by bazsi (subscriber, #63084)Parent article: Stable pages
I'm modifying a page in place at a high rate to keep the internal state of syslog-ng intact even in the case of a crash:
syslog-ng is following a logfile, its current position is kept in a file-backed memory region. In case the daemon is crashed the position remains there, so we can continue where we left off.
syslog-ng can update that page 100k/sec (especially if there are multiple such files and multiple threads reading), and I'm sure it's not waiting for writeback all the time, but that would probably negatively affect this and similar workloads.
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Stable pages Posted May 13, 2011 20:06 UTC (Fri) by dlang (✭ supporter ✭, #313) [Link]
if the modified page isn't getting written out, you aren't getting the safety that you are looking for.
Stable pages Posted May 17, 2011 20:29 UTC (Tue) by bazsi (subscriber, #63084) [Link]
it gets written out eventually. it's a dirty page after all. even if the process exits.
the only thing to prevent that is an OS level crash.
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