[linux-lvm] fsync() and LVM

Dietmar Maurer dietmar at proxmox.com
Sat Mar 14 09:07:31 UTC 2009

> Let's try to clear up the confusion.
> Kernel device-mapper (which lvm uses) does not support write barriers
> except in very restricted circumstances (when only one device is
> involved and the mapping is trivial).  If dm receives a write barrier
> which is not supported it notifies the caller (typically a filesystem)
> so appropriate action can be taken if it wishes.

Does that mean I should never use more than one device if I have
applications depending on fsync (databases)?

- Dietmar

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