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Re: [linux-lvm] fsync() and LVM



Greg Freemyer wrote:
I haven't seen anyone claim yet that there is support for fsync(), which
must return the status of the completion of the operation to the
application.  If it does, then the discussion could turn to performance.

Is your specific interest to ext3?

No, it is whether a useful fsync() is possible over LVM.

If so, I suggest you post a
question there along the lines of:

Device Mapper does not support barriers if more than one physical
device is in use by the LV.  If I'm using ext3 on a LV and I call
fsync() from user space, how is fsync() implemented.  Or is it not?

The point of fsync() is for an application to know that a write has been safely committed, as for example sendmail would do before acknowledging to the sender that a message has been accepted. The question isn't whether an application can call fsync() but rather whether it's return status is lying, making the underlying storage unsuitable for anything that needs reliability.

--
  Les Mikesell
   lesmikesell gmail com


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