[Users] new oVirt installation recommendations

[Jason Keltz]

I've been experimenting with oVirt 3.2 on some old hardware, and am now 
preparing to buy new hardware for using oVirt 3.3 in production.  I'm 
interested in any feedback about what I plan to purchase.  I want to 
keep the setup as simple as possible.  Our current environment consists 
of mostly CentOS 6.4 systems.

The combined oVirt engine and file server will be a Dell  R720 with dual 
Xeon E5-2660 and 64 GB of memory.   The server would have an LSI 9207-8i 
HBA connected to the SAS backplane.    The R720 enclosure has 16 x 2.5" 
disk slots.  I would get 2 x 500 GB NLSAS drives for mirrored md rood 
(raid1), use 12 slots for RAID10 SAS 10K rpm drives (either 600 GB or 
900 GB), and have an additional 2 spares.   Data storage would be 
virtual machines, and some associated data.  The O/S would be CentOS 6.4.

The nodes would be 3 x Dell R620, dual Xeon E5-2690, 128 GB memory, each 
with just a single, small NL SAS root drive.  There would be no other 
local storage.  All VMs would use the file server as the datastore.  The 
nodes would run oVirt node.

In terms of networking, each machine would have 4 ports - 2 x 1 Gb 
(bonded) giving machines access to "public" network (that we do not 
control).  The 2 x 10 Gb copper would be connected to a locally 
installed copper 10G switch that we fully control - 1 port used for 
storage, and  1 for management/consoles/VM migration.

A few additional notes ...

I chose to stick with software raid MD on the file server, mostly for 
cost, and simplicity.  I have a lot of experience good with MD, and 
performance seems reasonable.

I would have gone SSD for the file server root disk, but the cost from 
Dell for their SSD is prohibitive, and I want the whole system to be 
included in the warranty.  NLSAS is the cheapest disk that will have 
support for the duration of the warranty period (with Dell servers, SATA 
drives are only warranted for 1  year).

The nodes with 1 NLSAS drive... I've thought about replacing that with 
simply an SD card.  It's not clear if this the best solution, or how 
much space I would need on that card.  At least when I configure via the 
Dell web site, the biggest SD card it seems I can purchase with a server 
is 2 GB which doesn't seem like very much! I guess people guy bigger 
cards separately.   I know a disk will work, and give me more than 
enough space and no hassle.

I've chosen to keep the setup simple by using NFS on the file server, 
but I see a whole lot of people here experimenting with the new Gluster 
capabilities in oVirt 3.3.  It's not clear if that's being used in 
production, or how reliable that would be.  I really can't find 
information on performance tests, etc with Gluster and oVirt, in 
particular, with comparison of NFS and Gluster.   Would there be a 
performance advantage to using Gluster here? How would it work? by 
adding disk to the nodes, and getting rid of the file server (or at 
least turning the file server into a smaller engine only server)?  How 
would this impact the nodes in terms of their ability to handle VMs? 
(performance?)  I presently have no experience with Gluster whatsoever, 
though I'm certainly never against learning something new, especially 
should it benefit my project.  Unfortunately, as I'm positive everyone 
can attest for is that it's just trouble finding the number of hours in 
the day :)  There's one thing for sure - Gluster itself, while maybe not 
TOO complicated is still more complicated than an NFS only setup.

As I've mentioned before, we don't use LDAP for authentication, so I'll 
be restricted to one admin user at the moment unless I setup a separate 
infrastructure for oVirt authentication. That will be fine for a little 
while.  I understand that work may be underway for pluggable 
authentication with oVirt.  I'm not sure if that ties into any of the 
items on Itamar's list though. Itamar? :)  I was hoping to see that 
pluggable authentication model sooner rather than later so that I could 
write something to work with our custom auth system.

In terms of power management - my existing machines are using a Raritan 
KVM with Raritan power management dongles and power bars. I haven't had 
an opportunity to see if oVirt can manage the devices, but I guess if 
oVirt can't do it, I can continue to manage power through the KVM interface.

Any feedback would be much appreciated.

Thanks for your time.

Jason Keltz