From mboxrd@z Thu Jan 1 00:00:00 1970 From: g.danti@assyoma.it Subject: KVM in HA active/active + fault-tolerant configuration Date: Wed, 21 Aug 2013 13:02:31 +0200 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE To: Return-path: Received: from santino.mail.tiscali.it ([213.205.33.245]:41218 "EHLO santino.mail.tiscali.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751646Ab3HULHt (ORCPT ); Wed, 21 Aug 2013 07:07:49 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by spambox.assyoma.it (Postfix) with ESMTP id E6076255A for ; Wed, 21 Aug 2013 13:02:32 +0200 (CEST) Received: from spambox.assyoma.it ([127.0.0.1]) by localhost (spambox.assyoma.it [127.0.0.1]) (amavisd-new, port 10024) with LMTP id STzETOrwFXWW for ; Wed, 21 Aug 2013 13:02:31 +0200 (CEST) Received: from ceres.assyoma.it (mail.assyoma.it [1.1.8.246]) by spambox.assyoma.it (Postfix) with ESMTP id DC81A24CB for ; Wed, 21 Aug 2013 13:02:31 +0200 (CEST) Sender: kvm-owner@vger.kernel.org List-ID: Hi all, I have a question about Linux KVM HA cluster. I understand that in a HA setup I can live migrate virtual machine=20 between host that shares the same storage (via various methods, eg:=20 DRDB). This enable us to migrate the VMs based on hosts loads and=20 performance. =C3=ACMy current understanding is that, with this setup, an host crash = will=20 cause the VMs to be restarded on another host. However, I wonder if there is a method to have a fully fault-tolerant=20 HA configuration, where for "fully fault-tolerant" I means that an host= =20 crash (eg: power failures) will cause the VMs to be migrated to another= =20 hosts with no state change. In other word: it is possible to have an=20 always-synchronized (both disk & memory) VM instance on another host, s= o=20 that the migrated VM does not need to be restarted but only=20 restored/unpaused? For disk data synchronization we can use shared=20 storages (bypassing the problem) or something similar do DRDB, but what= =20 about memory? Thank you, regards.