On 1/7/08, Laurent Vivier <[EMAIL PROTECTED]> wrote: > Le lundi 07 janvier 2008 à 11:03 -0500, Javier Guerra a écrit : > > hopefully, it would now work with "-cache=off", don't you think? > > Well, I don't think the problem is at the host level but at the guest > level, because both instances of qemu share the host cache and thus > first instance should see changes made by the second instance (and > vice-versa).
that's what a cluster filesystem is designed to cope with (and in fact expects) > There are also some caches at qemu level to emulate DMA, for instance in > hw/ide.c it is MAX_MULT_SECTORS (16) which is 8 kB buffer, perhaps your > problem is here but "cache=off" doesn't remove this. > Did you try to change MAX_MULT_SECTORS to 1 ? nope, don't know enough of qemu internals... but if those caches can be flushed from the guest, the filesystem should do that when writing its metadata > What do you call a "cluster filesystem" ? GFS, OCFS2, etc. that is, filesystems that are designed to run on more than one host with shared block storage. usually that means FibreChannel or iSCSI, but on VMs, a common backing could work too (at least in theory). Xen manages it, at least on paravirtualized guests; hadn't tried on HVM guests. maybe the IDE-like emulation is too poor an interface to handle it. -- Javier ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
