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Re: fsync, rdiff-backup, wapbl, and WD Elements 1T drive

In article <>,
Matthew Mondor  <> wrote:
>On Mon, 31 Oct 2011 19:58:27 -0400
>Greg Troxel <> wrote:
>> Obligatory actual netbsd tech-kern content: It seems like we really need
>> a sync_synchronous(2) system call that guarantees that all file system
>> operations that have completed (syscall returned) before the issuance of
>> the sync_synchronous call are on disk before sync_synchronous returns.
>> It seems odd that for sync, there is no waiting, fsync seems to wait,
>> and fsync_range can flush or not flush caches, more or less.
>Hmm since in sync(2), the non-synchronous issue is noted as a bug:
>     sync() may return before the buffers are completely flushed.
>Does this mean that sync(2) should normally be synchronous and fixed to
>be, such that sync_synchronous(2) not be necessary?

Which sync man page are you reading? Ours has:

     Historically, sync() would schedule buffers for writing but not actually
     wait for the writes to finish.  It was necessary to issue a second or
     sometimes a third call to ensure that all buffers had in fact been writ-
     ten out.  In NetBSD, sync() does not return until all buffers have been


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