On Sun, 30 Dec 2007, John Plocher wrote: > Without having seen any of the details of this project, there > are two architectural level issues that jump out at me. One > is that of an incompatible change, the other is knowing about > a future train wreck.
The later (train wreck) is what Garrett eluded to when this thread was starting up. The fact is that people are aware of the LSI megasas driver, and Garrett rightfully pointed that out. To further complicate this is the licensing. I have no knowledge of what it is though, but know it's being batted back and forth in legal (both Sun and LSI). I suspect it could have to do with drivers that Dell released several years ago, but I don't know that. And to even further complicate the issue, Sun recentely reached an agreement to partner with Dell that was announced a short while ago. I do not know how all of this effects the driver, but suspect some might. > Issue 1: > > On SX, we currently have a mix of open and closed source > components that includes a closed driver for this chipset. > > This project seeks to replace that driver with a different one, > such that some new version of SX will behave differently. The only other addition here is that the driver is NOT actually putback, but it's work in progress. > The issue is "what are those differences?" If they are along > the lines of "something that works today will break tomorrow", > then from a systems engineering perspective, we have a problem, > and will need to take steps to address the disconnect. Yes, this is one of the issues, most certainly. It is believed by some, including myself that the megasas encompasses support for more devices than the mfi. > Issue 2: > > We know that the current state of the networking stack is > not very friendly to driver changes (renames, multiple > drivers for a single device, ...) This is not networking, but disk/storage. Same problem though. > If we have reason to believe that we will have multiple > drivers for the same network device, we know we will end up > with a problem when they both end up in the same system. > Because the system does not (yet) support this situation, > we need to take steps to avoid it. > > > What exactly those steps might be is beyond the scope of > this email discussion and into the realm of ARC review. > We all understand the conflicting desires that are in play, > as well as the technical hurdles. Our job is to chart a > course thru them all that gets us to the destination with > the fewest casualties. To add another twist to this, we also know that there are few, if any SCSI adapters that are supported, most HBAs are closed/proprietary. SCSI controllers should be welcome in a community repository, even if duplicated for a closed driver. Or at least to be available to someone who might want to use it. That is an important piece for the community. -- Alan DuBoff - Solaris x86 IHV/OEM Group
