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 free. 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 offering. 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 inconvenience. 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 vxscan. From: "Murdock, Matt" It depends on if EMC will void your warranty or support if you use MPXIO/SVM. 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 setup. 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 $.02. 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 into: 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 problem. 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 challenge. 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 stack. 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 sunmanagers@sunmanagers.org http://www.sunmanagers.org/mailman/listinfo/sunmanagersReceived on Sat Jun 3 09:16:56 2006
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