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Re: [Qemu-devel] [RFC 00/12] Qorum disk image corruption resiliency
From: |
Benoît Canet |
Subject: |
Re: [Qemu-devel] [RFC 00/12] Qorum disk image corruption resiliency |
Date: |
Fri, 3 Aug 2012 21:11:54 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Le Friday 03 Aug 2012 à 16:14:51 (+0000), Blue Swirl a écrit :
> On Thu, Aug 2, 2012 at 10:16 AM, Benoît Canet <address@hidden> wrote:
> > This patchset create a block driver implementing a qorum using three qemu
> > disk
> > images. Writes are mirrored on the three files.
> > For the reading part the three files are read at the same time and a vote is
> > done to determine which is the majoritary qiov version. It then return this
> > majoritary version to the upper layers.
> > When three differents versions of the data are returned by the lower layer
> > the
> > qorum is broken and the read return -EIO.
>
> It would be pretty easy to make the number of nodes and quorum
> threshold values for both read and write selectable. Then you could
> have for example 100 nodes and write quorum at 51 (for example, 49
> nodes offline). Obviously writing the same data 100 times sequentially
> would not give very high performance but it's a start.
For now the number of disk is hardcoded to 3. But most of the code is written
with a variable number of disk in mind: just quorum_open and quorum_vote would
need
to be rewritten with a few automatic changes across the code.
- Re: [Qemu-devel] [RFC 12/12] qorum: build feature into QEMU., (continued)
- [Qemu-devel] [RFC 08/12] blkverify: Make blkverify_iovec_clone() and blkverify_iovec_compare() public, Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 09/12] qorum: Add qorum_co_flush()., Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 11/12] qorum: Add qorum mechanism., Benoît Canet, 2012/08/02
- Re: [Qemu-devel] [RFC 00/12] Qorum disk image corruption resiliency, Eric Blake, 2012/08/02
- Re: [Qemu-devel] [RFC 00/12] Qorum disk image corruption resiliency, Anthony Liguori, 2012/08/02
- Re: [Qemu-devel] [RFC 00/12] Qorum disk image corruption resiliency, Blue Swirl, 2012/08/03
- Re: [Qemu-devel] [RFC 00/12] Qorum disk image corruption resiliency,
Benoît Canet <=