Powerpath v/s MPIO

Question

What benefits do we get if we configure powerpath instead of using the native Os mpio options? I need to decide for an environment having Windows & AIX hosts.

RRR · Answer

AFAIK MPIO is a pure failover solution (an HBA "owns" a LUN), so if an HBA fails, the other HBA takes over the I/O for that particular LUN.
PowerPath evenly distributes I/O over all HBA's plus does failover if an HBA fails.

I love PPath, since it's so much better for performance

Conor · Answer

PP has superior features (including migration enabler) compared to other multipathing and load balancing sw specially when it comes to EMC storage.

PowerPath has specially written load balancing policies that increase performance when attached to EMC arrays.

From a manageability perspective, its easier to manage all of your SAN hosts that use one failover software, rather than have an extra new set of commands to learn for each different platform.

Those are the main reasons that make PowerPath a better option than the native failover...
1. Features, 2. Performance, 3, Manageability

[think I should join the sales team after that pitch]

Conor

Allen Ward · Answer

I have to agree that PowerPath is definitely the way to go. My server experience is primarily Windows, and most of it was pre-MPIO, but the extra features you get from PP make it worth the additional cost.

We recently had it out with our Unix admins because they wanted to drop PP in favour of MPIO but we were able to convince them otherwise. They were thinking it would be easier to maintain and troubleshoot the environment without PP, but in reality the things they need to do to keep PP current and supported should be done anyway (e.g. patching and OS maintenance).

RRR · Answer

[think I should join the sales team after that pitch]Yeah, that makes two of us On the bright side: being sales we'll get big bonuses as well

Spril1967 · Answer

So i want to rise the question angain in these times where Windows Server 2008 have (after what i heard a pretty good) a native MPIO build in, and free of charge

is it so still good money to trow after PP

Regards from Denmark

Message was edited by: Kenneth Ditmar Hansen
Ditmar

Allen Ward · Answer

I haven't looked at the details of MPIO on Win2K8 yet, but I guess the answer still depends on what your requirements are and on what you consider "pretty good".

Maybe MPIO would be sufficient in a non production environment, but I think the load balancing alone would make it worthwhile for almost any real production host. That's just my opinion based on my experience with our environment though.

Conor · Answer

Great first post and answer G2 - welcome to the forum!

BrianMarsh · Answer

Another aspect is the increased complexity of configuring MPIO and balancing I/O load across I/O paths. After enabling MPIO (and rebooting), you have to configure it to claim the devices (reboot, #2). Then it is likely the Load Balancing policy will have to be changed (reboot, #3) as if you leave the default of failover for DMX, the load across FA's will become unbalanced. In the case of Clariion, MPIO will move all CLARiiON LUNs to a single Storage Processor on the CLARiiON array so to balance load across SP's, you'll need to balance servers (with all their LUNs) across the SP's instead of just LUNs.

Spril1967 · Answer

Thanks for all the answers, ill think we stick to PowerPath.Regards Kenneth Ditmar Hansen

lid3qe9 · Answer

We went from RHEL4 to RHEL5 enviroment and decided to switch from PP to MPIO under RHEL5. Our main reason was that we were changing kernel levels all I/O needed to be stopped to reinstall PP (because PP needs reinstalled when the kernel changes). Therefore to save a reboot into init1 and comment out all SAN volumes in /etc/fstab we decided to switch to RedHat OS provided dm-multipath which updated with the errata set.  If someone knows a way around this like how to upgrade the kernel without reinstalling PP please let me know. I'm posting this because we are looking around at performance information related to non-balanced paths after switching from PP to dm-multipath on RHEL5 Oracle RAC enviroments.

PowerPath

Powerpath v/s MPIO

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