[gpfsug-discuss] Used virtualization technologies for GPFS/Spectrum Scale

[Jonathan Buzzard]

On Mon, 2017-04-24 at 11:29 -0400, valdis.kletnieks at vt.edu wrote:
> On Mon, 24 Apr 2017 14:21:09 +0200, "service at metamodul.com" said:
> 
> > todays hardware is so powerful that imho it might make sense to split a CEC
> > into more "piece". For example the IBM S822L has up to 2x12 cores, 9 PCI3 slots
> > ( 4×16 lans & 5×8 lan ).
> 
> We look at it the other way around: Today's hardware is so powerful that
> you can build a cluster out of a stack of fairly low-end 1U servers (we
> have one cluster that's built out of Dell r630s). And it's more robust
> against hardware failures than a VM based solution - although the 822 seems
> to allow hot-swap of PCI cards, a dead socket or DIMM will still kill all
> the VMs when you go to replace it.  If one 1U out of 4 goes down due to
> a bad DIMM (which has happened to us more often than a bad PCI card) you
> can just power it down and replace it....

Hate to say but the 822 will happily keep trucking when the CPU
(assuming it has more than one) fails and similar with the DIMM's. In
fact mirrored DIMM's is reasonably common on x86 machines these days,
though very few people ever use it.

That said CPU failures are incredibly rare in my experience. The only
time I have ever come across a failed CPU was on a pSeries machine and
then it was only because the backup was running really slow (it was
running TSM) that prompted us to look closer and see what had happened.
Monitoring (Zenoss) was not setup to register the event because like
when does a CPU fail and the machine keep running!

I am not 100% sure on the 822 put I suspect that the DIMM's and any
socketed CPU's can be hot swapped in addition to the PCI card's which I
have personally done on pSeries machines.

However it is a stupidly over priced solution to run GPFS, because there
are better or at the very least vastly cheaper ways to get the same
level of reliability.

JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Fife, United Kingdom.