On 03/02/2018 11:42 AM, Aziz Rozyev wrote:
Of course it affects performance. But as for how much: it depends on
many factors. It's possible to build servers where the overall effect
will be negligible.
man page quote is related to the Valery’s argument that fsync wont affect
performance, forget it.
Yes, it has been suggested multiple times, the only problem is it's not
true. No matter how good server/storage you have, if you write to
unbacked memory buffers (which nginx does), you are toast.
It’s nonsense because you’re trying to solve the reliability problem at the
it has been multiple times suggested here already by maxim and Paul, that it’s
to invest to the good server/storage infrastructure, instead of fsyncing each
That's what really kills performance, because of the async nature of
nginx. That's why I'm proposing an option to do the fsync at the end of
the PUT (or maybe even the whole operation) in a thread(pool).
Regarding the DB server analogy, you’re still not save from the power outages
as long as your
transaction isn’t in a transaction log.
If you’re still consent with syncing and ready to sacrifice your time, try
mounting a file system
with ‘sync’ option.
If you care about performance and reliability, that's the way it has to
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