Billy Verreynne wrote:This was going to be my suggestion as well. You can do a lot more tuning with dm-multipath than powerpath as well.
Why taint the kernel with binary and proprietary vendor drivers? Each and every time you touch that kernel with even a minor patchset, proprietary drivers will cease to work as the kernel version changed.
Why not use standard multipath instead? Open Source. Ships by default with Linux enterpise kernels. Does everything that Powerpath does - and more.
Linux multipath/udev have their origins in some of the largest Linux cluster on this planet. It is robust software. And proven software.
We have been using multipath for many years now - and are still using it on VNX SANs.
Dude wrote:When I tested this on both Clariions and Symmetrix arrays on RHEL5 and RHEL6 to do performance comparisons between DM-Multipath, Veritas VxDMP, and PowerPath, PowerPath was consistently about 1-2% faster than DM-Multipath. I can't imagine paying for a 1-2% performance improvement over something that's free.
As far as I know, EMC Powerpath contains optimizations to device fail-over algorithms and I/O performance of specific EMC hardware, at least for MS Windows. I'm not saying that there will necessarily be any performance difference under Linux, but it might be something to evaluate. Manual tuning could be a real challenge.