Re: [Xen-users] Aoe or iScsi???

[Bart Coninckx <bart.coninckx@xxxxxxxxxx>]

On Monday 05 July 2010 14:27:20 Gilberto Nunes wrote:
> I see...
> 
> Well... Let me give more details here...
> 
> I delivery aoe with a dedicated gigalan crossover between NAS Server and
> Xen Server...
> So, all traffic between this two server ran over this cross cable...
> 
> The Xen server is a Dell PowerEdge 1950 and NAS Server is an Intel based
> PC as I said before...
> 
> Sometimes, AoE seems lost connection with vblade, then one or two VM get
> down, and I can't return this VM... So I restart both servers!
> (Amazing!!)
> 
> I looking for better solutions here... Maybe I'll install iSCSI and take
> some tests...
> 
> Thanks for reply...
> 
> Em Seg, 2010-07-05 Ãs 14:14 +0200, Bart Coninckx escreveu:
> > On Monday 05 July 2010 14:08:48 Gilberto Nunes wrote:
> > > Hi people...
> > >
> > > Here we use Xen 4 with Debian Lenny... We're using kernel 2.6.31.13
> > > pvops...
> > > As a storage system, we use AoE devices...
> > > So, we installed VM's on AoE partition... The "NAS" server is a Intel
> > > based baremetal with SATA hard disc...
> > >
> > > However, sometime I feeling that VM's is so slow...
> > >
> > > Also, all VM has GPLPV drivers installed...
> > >
> > > So, I am thing about change AoE to iSCSCI...
> > >
> > > However, I have many doubt with this procedure... Is it iSCSI better
> > > than AoE???
> > >
> > > Please, if someboy can clarify this matter, I'll be very thanks...
> > >
> > > Regards
> > >
> > >
> > >
> > > Gilberto Nunes
> > > TI
> > > Selbetti GestÃo de Documentos
> > > Telefone: +55 (47) 3441-6004
> > > Celular: +55 (47) 8861-6672
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > Xen-users mailing list
> > > Xen-users@xxxxxxxxxxxxxxxxxxx
> > > http://lists.xensource.com/xen-users
> >
> > iSCSI will never outperform AoE in my opinion. But in stead of randomly
> > switching technologies, I think you better try to find the culprit
> > before. Like your storage itself for instance. SATA is not the fastest.
> > What  kind of RAID are you using and such ... (iotop?). Also what does
> > your storage network look like. These can all be bottlenecks.
> >
> > B.
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
> 
> Gilberto Nunes
> TI
> Selbetti GestÃo de Documentos
> Telefone: +55 (47) 3441-6004
> Celular: +55 (47) 8861-6672
> 

That's working in reverse order. You need to test the speed of your storage 
locally first. That means without iSCSI, AoE ot whatever. If this already is 
slower than your network speed, you can do whatever you want with AoE or 
iSCSI, it won't matter. Optimally you would test the IOPS, but you will get 
quite a good indication by running bonnie++ locally. If you hit less than 120 
MB/sec in reading and/or writing, you have your bottleneck. Changing RAID5 to 
RAID50 or RAID1 to  RAID10 can then already do a world of good. 
If that is not the bottleneck, you might consider upgrading your network path 
by using NIC bonding or multipathing. 





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