prasad jlv wrote: > Hmm, I thought SVM mirrors perfomed reads in a round-robin way too
> and If I am mirroring across controllers, am I achieving the same? That is correct..however its across 2 sub-mirrors. What mpxio gets is round-robinning to the same drive across 2 controllers. Putting it in another way, when you don't use mpxio, you dedicate each controller to set of disks. When you enable mpxio you effectively share the controllers across both sets of drives. Hope that clarifies. -Sanjay > or is my assumption about SVM's read policy incorrect? > > -- prasad > > > > */Sanjay Nadkarni <Sanjay.Nadkarni at sun.com>/* wrote: > > > One of the advantages of mpxio is that it load balance requests > across > the controllers. Let's assume 12 read requests occurs. Since you > have a > mirror, they will be round-robin'ed. 6 per submirror. Now if the > controller on the submirror is busy processing some other I/O, > then the > read requests will be queued. If you have mpxio, that I/O could > potentially be dispatched from the other controller. > > Of course it's obvious that your load has to be fairly high for this > situation to pay off. > > > -Sanjay > > prasad wrote: > > >I am trying to understand the benefits of MPXIO in our situation.... > > > >We have a V880 with the backplane expansion kit and 12 x 73 GB > disks but with MPXIO disabled. format(1M) displays 24 disks with 2 > paths to each of the 12 disks (c1tXd0 and c2tXd0) and we are > mirroring our disks using SVM in the following way: > > > >d500 -m d400 d700 1 > >d400 1 1 c1t0d0s0 > >d700 1 1 c2t8d0s0 > >.......................... > > > >My questions are: > > > >* Since we are accessing the mirrors thru unique controllers i.e. > c1 & c2 are we doing load balancing? I wonder how the system would > behave if one of the controllers failed? > >* How would MPXIO help in the above scenario? Are we doing > something terribly wrong by not enabling MPXIO? > > > >TIA, > >-- prasad > >This me! ssage posted from opensolaris.org > >_______________________________________________ > >lvm-discuss mailing list > >lvm-discuss at opensolaris.org > > > > > > > ------------------------------------------------------------------------ > Brings words and photos together (easily) with > PhotoMail > <http://us.rd.yahoo.com/mail_us/taglines/PMall/*http://photomail.mail.yahoo.com> > > - it's free and works with Yahoo! Mail.
