Re: [Xen-API] redundant xcp server with drbd

[Denis Cardon <denis.cardon@xxxxxxxxxxxxxxxxxxxxxx>]

Hi Andreas,

> Hi there maybe have a look at GlusterFs -
>
> We have a running setup here (8 Nodes, 100 VMs) that share localstorage
> - but we use GlusterFS (running in Dom0 - yes something you should not
> do under no circumstances I know) instead of DRBD - and of course there
> is no iSCSI or other block-level storage in this set-up but NFS or just
> a BIG folder of apparently local Storage using native glusterFS that
> works well by now
>
> - maybe you'll have alook at such an option ...
definitly looks interesting ! Moreover you can use thin provisioning 
with real thin vhd :-) How is the setup behaving in disaster recovery 
scenarios?
If you severe the link in between the two servers and the vhd needs to 
grow, how does the slave server knows the next few blocks are still 
available and have not been handed down to another vhd on the master server?
Cheers,

Denis

> Gruss
>
> Andreas Balg
>
>
>
>
>
> Am Dienstag, 06. März 2012 11:22 CET, George Shuklin
> <george.shuklin@xxxxxxxxx> schrieb:
>
> > Good day.
> >
> > We've tried that for internal laboratory. Problem: sometime drbd do
> > additional IO and making storage out of sync. We've spend few weeks on
> > this set up (primary/primary drbd, and iscsi export with LVMoISCSI SR),
> > but it getting unstable after some time, so we gave up.
> >
> >
> >
> > On 06.03.2012 13:47, Denis Cardon wrote:
> > > Hello everyone,
> > >
> > > I wanted to know if any of you had some experience with building a
> > > redundant xcp/xenserver cluster based on drbd. In this setup I would
> > > like to avoid a separate iscsi SAN, and have replicated local storage.
> > >
> > > There are docs on the internet showing how to set up a dual primary
> > > drbd SR on xenserver/xcp. It works fine with live migration and all,
> > > but when trying disaster scenario, like severing the drbd replication
> > > link, one gets a split brain scenario that cannot be unsolved. It
> > > should be doable if xapi had a smart understanding of drbd, but
> > > currently it is just a SR like others. So it is a no-go for the time
> > > being.
> > >
> > > I also tried a drbd primary-secondary scenario, with re-export with
> > > iet iscsi target, but for the moment I have unresolved performance
> > > issues (will try also with scst target).
> > >
> > > So I wanted to know if any of you had any experience or hints with
> > > this kind of setup : a dual active/active XCP servers with local SR
> > > replicated with primary-secondary DRBD, re-exported with iscsi or aoe
> > > or whatever.
> > >
> > > Cheers,
> > >
> > > Denis Cardon
> > >
> >
> >
> > _______________________________________________
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> > xen-api@xxxxxxxxxxxxx
> > http://lists.xen.org/cgi-bin/mailman/listinfo/xen-api
>
>
>
> This body part will be downloaded on demand.

--
Denis Cardon
Tranquil IT Systems
44 bvd des pas enchantés
44230 Saint Sébastien sur Loire
tel : +33 (0) 2.40.97.57.57
http://www.tranquil-it-systems.fr


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