On 07/21/2010 10:43 AM, Takuya Yoshikawa wrote: > >> If the VM can't do anything, you're safe. Of course a crash doesn't mean >> a VM can't do anything, you typically need to isolate it by resetting >> the host or having a switch disconnect its storage and network. >> >> > Thanks, > We are starting to manage the "only VM crashed" case by HA. > So yes, we need to reset the host. > It may be sufficient to issue a sync(2). >> I believe nothing special is needed, as long as a crash means both the >> qemu and host kernel crashed. If only qemu crashed, then the writeback >> case needs buffers flushed. >> >> > My main concern is only qemu crashed and host is alive case. > > Host memory is typically large, so we want to eliminate flushing everything > if possible. > > So we don't need to flush in the case of writethrough = RHEL default ? > No. But you do need to unmount the underlying host filesystem. I recommend using cache=none and direct volume access, this is easier to guarantee integrity. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
