SUMMARY: EMC Powerpath v. Sun MPXIO for reliable duel attached fibre SAN?

From: Geoff Lane <>
Date: Sat Jun 03 2006 - 09:16:12 EDT
Sorry for the long delay in posting the summary.

I've included all the replies below.

I asked...

If you ask EMC about reliable dual attached SAN and HBA fail-over they will
insist that the only way to do it is to use Powerpath and possibly Veritas
Volume Manager.  Yet within Solaris you can, as far as I can understand from
the documentation, get the same functionality using MPXIO and possibly SVM.

On the server the EMC solution is hugely expensive, the Sun solution is

Has anybody compared the two solutions in a real world situation and can
share their observations?


From: Brett Lymn

Not with powerpath.  We were using the HP equivalent called SecurePath
and have just completed a program of work of migrating off of
SecurePath and going to MPXIO on all our machines.  We found that the
performance of SecurePath was lower than MPXIO by a noticable amount,
not just user perception but running bonnie++ in both scenarios showed
that MPXIO was far superior.  You get full Sun support of the drivers
and, finally, the tools to manage the configuration of the fabric
devices under MPXIO are (of course) well integrated and Just Work.

I would be very dubious about any venduh that are trying to sell you
their horribly expensive multipathing software - see if you can get it
on eval and check out the performance and robustness vs Sun's

From: "joe fletcher" 

You might want to look at a post from a couple of days ago which mentions
some of the limitations of mpxio. A keyword search in the archives on mpxio
will find it. One of the things it mentions was that mpxio doesn't ever do
active-active like Powerpath.
From: Koef 

I have a dozen Sun machines doing MPxIO to EMC storage. Failover has worked
flawlessly on all these machines. Be sure you get Sun branded HBA's though,
because EMC won't support running Sun drivers/MPxIO on non-Sun branded (ie.
original Qlogic, Emulex, etc.) cards. If you can live without EMC
certification, original cards run with Sun drivers equally well.

I am surprised EMC told you that PowerPath is the only way. Last time I
checked, MPxIO was definitely listed in their Compatibility Matrix.

From: Adam Levin

I'd be very interested in the responses.  We used MPXIO a little over a 
year ago going to a pair of Brocade switches to a NetApp.  The 
multipathing seemed to work fine.  The only problem we had was when one of 
the switches failed in an odd way -- it was up, but non-responsive.  The 
MPXIO was unable to determine it was down, and caused problems (this was 
an Oracle server running on a Sun V890 with Solaris 8).

We are no longer using SAN at this time.

From: Joshua Clark

We use both Veritas DMP and Sun's mpxio (Now called Sun StorEdge Traffic
Manager). So far my experience with both has been positive. We've tested
both multipathing solutions on production servers and haven't had any
problems. I've replaced array controllers with machines online (thereby
eliminating one path to the disks) and the hosts running mpxio and dmp
didn't hiccup.  The only downside to TrafficManager is the long
/dev/dsk/ctd names you get, which are based on the WWN, but that's a minor

I've never tested the EMC solution.

Hope this helps.

From: JV 

I have 6800s with the following:

on hba 1, Qlogic cards connect to an EMC DMX with powerpath
on hba 2, Qlogic cards connect to Sun 3510s with MPxIO
on hba 3, JNI cards connect to fiber LTO gen1 tape drives with neither
powerpath or mpxio. FC-AL targeting on tape devices does NOT allow
failover pathing!

Of course there are 3 different switches (actually 6!) for the above
fabrics. In every case, you use Veritas Volume Mgr for storage anyway.
I have never heard of anyplace that could afford EMC licensing that
could NOT also afford Veritas. That's like buying a new Mercedes and
then putting hub cabs on bargin tyres.

 It is possible to restrict powerpath/mpxio to specific paths/hbas in
qlc.conf and such, and with other symxxxx something that I can't
remember now.

I have never had "reliability" issues with either product. I yanked
cables and tail -f /var/adm/messages and either product fails over just
fine. Veritas DMP is the one which did not autofailBACK in the past,
you might have to help it along with cfgadm, devfsadm, vxdmpadm and

From: "Murdock, Matt"

It depends on if EMC will void your warranty or support if you use
	We have a customer who uses EMC PowerPath and Veritas with great
success. SVM has always been a performance hog. 
	MPXIO vs. VXDMP is, kind of irrelevant, it's just how you want
to work with the device naming of the luns. MPXIO lets you use the
cxtxdx naming, while VXDMP uses the cxtWWNd0 naming. Power Path masks
off the WWN and gives Veritas a reasonable cxtxdx naming scheme.
	If you are using Sun Cluster, be VERY CAUTIOUS with the EMC
	For general statement, MPXIO and SVM should work great with EMC
SAN's on Solaris 10. With Solaris 8, 9....look into the Veritas and
PowerPath roadmap.

From: "Lineberger, Aaron" 

I use SVM with MPXIO and qlc drivers and have tested it thoroughly with
regards to path failovers, pulling cables, dropping entire fabrics, and
dynamic reconfiguration of IO boards out of E25K domains. As long as
it's set up correctly it work's flawlessly. I've also tested using
Qlogic HBA with Qlogic drivers and have never had a problem. Just my

From: "Aseltine, Dick" 

If you already have Veritas Volume Manager then I would suggest using
DMP. Not sure if EMC supports MPXIO and I don't believe SVM is a
solution. EMC works fantastic but like you mentioned it is very costly.
Sorry I couldn't have of more help. Good luck.

From: "Hallbauer, Joerg" 

Sure, we use a mix of PowerPath and SUN's MPXIO, and I hate SUNs
solution. As a matter of fact, I hate this, as well as the SUN HBAs and
the drivers that come with them. Just some of the issues we have run

1) With MPXIO there is now clean interface to see what is going on like
with EMC's powermt command.

2) We have run into all kinds of issues with some of our vendors when we
have trouble. Fr example, we had some problems with our HP/XP1024 and
scsi-3 persistent reservations. It turned out that it was a problem with
the HP micro-code, but we spent a lot of time trying to figure this out,
and ran do a lot of blind alleys thinking that maybe MPXIO was the

3) MPXIO doesn't provide the fine level of control that Powerpath does.
With Powerpath I can do things like take 4 HBAs and dedicate two to one
application and two to another while also using them to back up each
other (i.e. if I lose an HBA, then Powerpath will automatically start
using one of the other HBAs to make up for it).

4) SUN support has been less than sterling. Trying to find someone at
SUN who knows what they are talking about in regards to MPXIO has been a

5) They provide few options on the load balancing algrythem than either
EMC or Veritas.

6) If you are running EMC arrys, then EMC has put smarts into Powerpath
to help you with things like TimeFinder and SRDF integration, etc. 

So, I would stay away from SUN's MPXIO. If you are running Veritas
(highly recommended) them you can use DMP. Just make sure you are
running 4.x if you are going that way. If you want the Cadillac, go with
PowerPath. This is especially true if you are connecting to EMC arrays.

From: "Fernando Boveda" 

As you said :

1.- EMC will always recommend to use Power Path with Solaris and to use
Veritas Volume Manager. All this costs.

2.- If you have a Solaris Server , you can choose to use mpxio and Veritas
Volume Manager. You must pay for the Veritas license.

3.- You can choose to use Solaris Volume Manager with Solaris and mpxio and
all this is for free in the Solaris Operating System.

All this combination works, the problem is that you need someone to share
with you how to install them.

As an IT Consultant that works with Sun, EMC, Veritas and Oracle I always
deal with this questions. The best choice in complex environments for me is
Solaris with mpxio and Veritas Volume Manager or the External Storage and
Solaris Volume Manager for the internal drives and the Operating System.

If your installation is no so complex you can do it with Solaris Volume
Manager as well.

From: ian.mcginley

EMC will provide you with powerpath for multipathing for their devices 
only. MPXIO/STMS will provide you with multipath for any supported storage 
array provided you are using the SUN QLogic/Emulex SAN cards and driver 

VxVM is technically more mature and feature rich than SVM (in my opinion). 
However you pay for it. You will need to work out your SAN disk 
requirements before deploying either.

For example if all you want is failover of Fabric path's during regular 
operation on a single node, then MPXIO/STMS will do this fine. If you want 
to do it between two nodes for HA/DR, then it can be done without VxVM, 
but it makes it a _LOT_ easier (can be done with naked luns, eg no volume 
management). SVM supports Metaset's which are similar to the VxVM disk 
group technology, however I believe they are only supported in a Sun 
Cluster environment.

VxVM makes node disk group failover simple. Thats what I would primarily 
use it for these days.

Geoff Lane

Sure, drinking kills brain cells, but only the weak ones.
sunmanagers mailing list
Received on Sat Jun 3 09:16:56 2006

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