From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49315) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1byzUX-0002Nx-G9 for qemu-devel@nongnu.org; Tue, 25 Oct 2016 07:02:02 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1byzUT-0005Ro-Hn for qemu-devel@nongnu.org; Tue, 25 Oct 2016 07:02:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47240) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1byzUT-0005Rh-Bw for qemu-devel@nongnu.org; Tue, 25 Oct 2016 07:01:57 -0400 References: <1475035789-685-1-git-send-email-ashish.mittal@veritas.com> <20160930083606.GA5411@stefanha-x1.localdomain> <1cec99e2-eb93-b897-bf7d-8ae7bd70ed17@redhat.com> <8552F2D6-EA05-452B-A90F-61BF0C213E17@veritas.com> From: Paolo Bonzini Message-ID: Date: Tue, 25 Oct 2016 13:01:48 +0200 MIME-Version: 1.0 In-Reply-To: <8552F2D6-EA05-452B-A90F-61BF0C213E17@veritas.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v7 RFC] block/vxhs: Initial commit to add Veritas HyperScale VxHS block device support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Ketan Nilangekar Cc: Stefan Hajnoczi , Ashish Mittal , "qemu-devel@nongnu.org" , "kwolf@redhat.com" , "armbru@redhat.com" , "berrange@redhat.com" , "jcody@redhat.com" , "famz@redhat.com" , Ashish Mittal , Abhijit Dey On 25/10/2016 07:07, Ketan Nilangekar wrote: > We are able to derive significant performance from the qemu block > driver as compared to nbd/iscsi/nfs. We have prototyped nfs and nbd > based io tap in the past and the performance of qemu block driver is > significantly better. Hence we would like to go with the vxhs driver > for now. Is this still true with failover implemented outside QEMU (which requires I/O to be proxied, if I'm not mistaken)? What does the benefit come from if so, is it the threaded backend and performing multiple connections to the same server? Paolo > Ketan > > >> On Oct 24, 2016, at 4:24 PM, Paolo Bonzini >> wrote: >> >> >> >>> On 20/10/2016 03:31, Ketan Nilangekar wrote: This way the >>> failover logic will be completely out of qemu address space. We >>> are considering use of some of our proprietary >>> clustering/monitoring services to implement service failover. >> >> Are you implementing a different protocol just for the sake of >> QEMU, in other words, and forwarding from that protocol to your >> proprietary code? >> >> If that is what you are doing, you don't need at all a vxhs driver >> in QEMU. Just implement NBD or iSCSI on your side, QEMU already >> has drivers for that. >> >> Paolo