I am running a lot of KVM virtual machines, which open the hard disk image with the
I understand, according to the
open() man page, that using
O_DIRECT will try to bypass the Linux page cache when writing to a file, but does that apply to block devices as well? (for instance when the hard disk image is a LVM volume, or a ZFS zvol)
NB: the use case of
O_DIRECT here, is that the guest is already maintaining its own page cache, so it makes no sense to duplicate that on the host.