<div dir="ltr">Hi Lars, <br><div dir="ltr"><div><br></div><div>I will have a look on your suggestions. </div><div><br></div><div>thanks</div></div><div class="gmail_quote">On Wed, Oct 31, 2012 at 1:43 PM, Lars Ellenberg <span dir="ltr"><<a href="mailto:lars.ellenberg@linbit.com" target="_blank">lars.ellenberg@linbit.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On Wed, Oct 31, 2012 at 09:33:02AM +0000, Maurits van de Lande wrote:<br>
> Hello Zohair,<br>
><br>
> >So If I don't have real fencing device, I can't get a cluster?<br>
><br>
> It depends, I have some clusters without fencing, they are mainly for<br>
> virtualization. The cluster is configured not to relocate the services<br>
> in case of a failure. I do this manually. (all services are<br>
> redundant) The Virtual Machine configuration files are stored on a<br>
> GFS2 file system. I configured this file system to be always available<br>
> (also when quorum is lost). Because I do all the recovering manually<br>
> this does not matter, also no data is written to the GFS2 file system.<br>
><br>
> So, you can have a cluster without fencing if a quorum loss does not<br>
> corrupt your data. You should also set the cluster timeout's in such a<br>
> way that even with a WAN connection the cluster does not loose quorum<br>
> during normal operation. (I have not tried this)<br>
><br>
> For SAMBA you might need "clustered SAMBA" <a href="http://ctdb.samba.org/samba.html" target="_blank">http://ctdb.samba.org/samba.html</a><br>
<br>
</div>clustered samba on GFS2 via WAN to remote locations with bandwidth constraints,<br>
not to speak of latency and possible flakyness of the link.<br>
<br>
very very VERY BAD idea.<br>
<br>
cluster file system accros a WAN: already a bad idea.<br>
<br>
cluster file system without fencing is a sure subscription to data loss.<br>
<br>
Cluster file systems are very sensitive to latency,<br>
both storage latency and network latency (for the DLM component).<br>
So even if you would manage to get it working,<br>
the performance of it would sucksucksuck big time<br>
(on a WAN with bandwidth and latency constraints ...).<br>
<br>
In a word: Don't.<br>
<br>
Maybe look again why you think rsync does not work for you,<br>
use csync2, couple it with inotify maybe,<br>
look into lsyncd (which does the inotify part, and can by coupled with<br>
both rsync or csync2 or any other similar tool), ...<br>
<div class="im"><br>
> Did you have a look at glusterfs? <a href="http://www.gluster.org/" target="_blank">http://www.gluster.org/</a> It supports<br>
> synchronization (I do not know if it also works over a WAN connection)<br>
> But it has nothing to do with drbd. The drbd 8.3 branch is very<br>
> mature I do not know if this is the same for glusterfs.<br>
><br>
> Best regards,<br>
><br>
> Maurits<br>
><br>
><br>
> Van: <a href="mailto:drbd-user-bounces@lists.linbit.com">drbd-user-bounces@lists.linbit.com</a> [mailto:<a href="mailto:drbd-user-bounces@lists.linbit.com">drbd-user-bounces@lists.linbit.com</a>] Namens Zohair Raza<br>
> Verzonden: woensdag 31 oktober 2012 9:51<br>
> Aan: Felix Frank<br>
> CC: <a href="mailto:drbd-user@lists.linbit.com">drbd-user@lists.linbit.com</a><br>
> Onderwerp: Re: [DRBD-user] GFS2 freezes<br>
><br>
> So If I don't have real fencing device, I can't get a cluster?<br>
><br>
> My requirement is to synchronized two Samba boxes between remote<br>
> locations, I can't use rsync because of bandwidth consumption and<br>
> system processing each time it will run it will go through each file<br>
> and see if it is synced or not.<br>
><br>
> While GFS seemed to be the right option, but as two servers are<br>
> distant from each other I can not have fencing device as it may<br>
> experience power outage or network failures quite often.<br>
><br>
> What do you guys suggest in such scenario?<br>
><br>
> Regards,<br>
> Zohair Raza<br>
><br>
><br>
</div><div class="im">> On Wed, Oct 31, 2012 at 12:30 PM, Felix Frank <<a href="mailto:ff@mpexnet.de">ff@mpexnet.de</a><mailto:<a href="mailto:ff@mpexnet.de">ff@mpexnet.de</a>>> wrote:<br>
> On 10/31/2012 12:02 AM, Lars Ellenberg wrote:<br>
> >>> Manual fencing is not in any way supported. You must be able to call<br>
> >>> > > 'fence_node <peer>' and have the remote node reset. If this doesn't<br>
> >>> > > happen, your fencing is not sufficient.<br>
> >> > fence_node <peer> doesn't work for me<br>
> >> ><br>
> >> > fence_node node2 says<br>
> >> ><br>
> >> > fence node2 failed<br>
> > Which is why you need a *real* fencing device<br>
> > for automatic fencing.<br>
> ...which is bound to sound more than a little cryptic to the<br>
> uninitiated, I assume.<br>
><br>
> An example for a "classical" fencing method is a power distribution unit<br>
> with network access. The surviving node accesses the PDU and cuts the<br>
> power to its peer.<br>
> This is just one example. Similar results can be achieved using<br>
> IPMI/ILOM technologies etc.<br>
><br>
> HTH,<br>
> Felix<br>
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<br>
</div><div class="im HOEnZb">--<br>
: Lars Ellenberg<br>
: LINBIT | Your Way to High Availability<br>
: DRBD/HA support and consulting <a href="http://www.linbit.com" target="_blank">http://www.linbit.com</a><br>
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