Re: [ovirt-users] iSCSI and multipath

Hi Nicolas, Which DC level are you using? iSCSI multipath should be supported only from DC with compatibility version of 3.4

regards, Maor On 06/09/2014 01:06 PM, Nicolas Ecarnot wrote: > Hi, > > Context here : > - 2 setups (2 datacenters) in oVirt 3.4.1 with CentOS 6.4 and 6.5 > hosts > - connected to some LUNs in iSCSI on a dedicated physical network > > Every host has two interfaces used for management and end-user LAN > activity. Every host also have 4 additional NICs dedicated to the > iSCSI > network. > > Those 4 NICs were setup from the oVirt web GUI in a bonding with a > unique IP address and connected to the SAN. > > Everything is working fine. I just had to manually tweak some points > (MTU, other small things) but it is working. > > > Recently, our SAN dealer told us that using bonding in an iSCSI > context > was terrible, and the recommendation is to use multipathing. > My previous experience pre-oVirt was to agree with that. Long story > short is just that when setting up the host from oVirt, it was so > convenient to click and setup bonding, and observe it working that I > did > not pay further attention. (and we seem to have no bottleneck yet). > > Anyway, I dedicated a host to experiment, I things are not clear to > me. > I know how to setup NICs, iSCSI and multipath to present the host OS a > partition or a logical volume, using multipathing instead of bonding. > > But in this precise case, what is disturbing me is that many layers > described above are managed by oVirt (mount/unmount of LV, creation of > bridges on top of bonded interfaces, managing the WWID amongst the > cluster). > > And I see nothing related to multipath at the NICs level. > Though I can setup everything fine in the host, this setup does not > match what oVirt is expecting : oVirt is expecting a bridge named as > the > iSCSI network, and able to connect to the SAN. > My multipathing is offering the access to the partition of the LUNs, > it > is not the same. > > I saw that multipathing is talked here : > http://www.ovirt.org/Feature/iSCSI-Multipath > > I here read : >> Add an iSCSI Storage to the Data Center >> Make sure the Data Center contains networks. >> Go to the Data Center main tab and choose the specific Data >> Center >> At the sub tab choose "iSCSI Bond" > > The only tabs I see are "Storage/Logical Networks/Network > QoS/Clusters/Permissions". > > In this datacenter, I have one iSCSI master storage domain, two iSCSI > storage domains and one NFS export domain. > > What did I miss? > >> Press the "new" button to add a new iSCSI Bond >> Configure the networks you want to add to the new iSCSI Bond. > > Anyway, I'm not sure to understand the point of this wiki page and > this > implementation : it looks like a much higher level of multipathing > over > virtual networks, and not at all what I'm talking about above...? > > Well as you see, I need enlightenments. >