From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: Are there plans to achieve ram live Snapshot feature? Date: Fri, 09 Aug 2013 17:38:12 +0200 Message-ID: <52050CE4.6000306@redhat.com> References: <33FB050264B7AD4DBD6583581F2E03104B764728@nkgeml511-mbx.china.huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "aliguori@us.ibm.com" , "paul@codesourcery.com" , "kvm@vger.kernel.org" , "avi@redhat.com" , "mtosatti@redhat.com" , "qemu-devel@nongnu.org" To: Chijianchun Return-path: Received: from mail-ea0-f176.google.com ([209.85.215.176]:35568 "EHLO mail-ea0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964963Ab3HIPiq (ORCPT ); Fri, 9 Aug 2013 11:38:46 -0400 Received: by mail-ea0-f176.google.com with SMTP id q16so2120355ead.35 for ; Fri, 09 Aug 2013 08:38:45 -0700 (PDT) In-Reply-To: <33FB050264B7AD4DBD6583581F2E03104B764728@nkgeml511-mbx.china.huawei.com> Sender: kvm-owner@vger.kernel.org List-ID: Il 09/08/2013 12:20, Chijianchun ha scritto: > Now in KVM, when RAM snapshot, vcpus needs stopped, it is Unfriendly > restrictions to users. > > Are there plans to achieve ram live Snapshot feature? > > in my mind, Snapshots can not occupy additional too much memory, So when > the memory needs to be changed, the old memory page is needed to flush > to the file first. But flushing to file is too slower than memory, and > when flushing, the vcpu or VM is need to be paused until finished > flushing, so pause...resume...pause...resume............., more and > more slower. > > Is this idea feasible? Are there any other thoughts? > This looks very similar to postcopy migration (you can Google it). The infrastructure for postcopy migration could be used for this as well. Paolo