On Tue, Apr 20, 2010 at 12:54 AM, jvrao <jv...@linux.vnet.ibm.com> wrote: > Mohammed Gamal wrote: >> On Tue, Apr 13, 2010 at 9:08 PM, jvrao <jv...@linux.vnet.ibm.com> wrote: >>> jvrao wrote: >>>> Alexander Graf wrote: >>>>> On 12.04.2010, at 13:58, Jamie Lokier wrote: >>>>> >>>>>> Mohammed Gamal wrote: >>>>>>> On Mon, Apr 12, 2010 at 12:29 AM, Jamie Lokier <ja...@shareable.org> >>>>>>> wrote: >>>>>>>> Javier Guerra Giraldez wrote: >>>>>>>>> On Sat, Apr 10, 2010 at 7:42 AM, Mohammed Gamal >>>>>>>>> <m.gamal...@gmail.com> wrote: >>>>>>>>>> On Sat, Apr 10, 2010 at 2:12 PM, Jamie Lokier <ja...@shareable.org> >>>>>>>>>> wrote: >>>>>>>>>>> To throw a spanner in, the most widely supported filesystem across >>>>>>>>>>> operating systems is probably NFS, version 2 :-) >>>>>>>>>> Remember that Windows usage on a VM is not some rare use case, and >>>>>>>>>> it'd be a little bit of a pain from a user's perspective to have to >>>>>>>>>> install a third party NFS client for every VM they use. Having >>>>>>>>>> something supported on the VM out of the box is a better option IMO. >>>>>>>>> i don't think virtio-CIFS has any more support out of the box (on any >>>>>>>>> system) than virtio-9P. >>>>>>>> It doesn't, but at least network-CIFS tends to work ok and is the >>>>>>>> method of choice for Windows VMs - when you can setup Samba on the >>>>>>>> host (which as previously noted you cannot always do non-disruptively >>>>>>>> with current Sambas). >>>>>>>> >>>>>>>> -- Jamie >>>>>>>> >>>>>>> I think having support for both 9p and CIFS would be the best option. >>>>>>> In that case the user will have the option to use either one, >>>>>>> depending on how their guests support these filesystems. In that case >>>>>>> I'd prefer to work on CIFS support while the 9p effort can still go >>>>>>> on. I don't think both efforts are mutually exclusive. >>>>>>> >>>>>>> What do the rest of you guys think? >>>>>> I only noted NFS because most old OSes do not support CIFS or 9P - >>>>>> especially all the old unixes. >>>>>> >>>>>> I don't think old versions of MS-DOS and Windows (95, 98, ME, Nt4?) >>>>>> even support current CIFS. They need extra server settings to work >>>>>> - such as setting passwords on the server to non-encrypted and other >>>>>> quirks. >>>>>> >>>>>> Meanwhile Windows Vista/2008/7 works better with SMB2, not CIFS, to >>>>>> properly see symlinks and hard links. >>>>>> >>>>>> So there is no really nice out of the box file service which works >>>>>> easily with all guest OSes. >>>>>> >>>>>> I'm guessing that out of all the filesystems, CIFS is the most widely >>>>>> supported in recent OSes (released in the last 10 years). But I'm not >>>>>> really sure what the state of CIFS is for non-Windows, non-Linux, >>>>>> non-BSD guests. >>>>> So what? If you want to have direct host fs access, install guest >>>>> drivers. If you can't, set up networking and use CIFS or NFS or whatever. >>>>> >>>>>> I'm not sure why 9P is being pursued. Does anything much support it, >>>>>> or do all OSes except quite recent Linux need a custom driver for 9P? >>>>>> Even Linux only got the first commit in the kernel 5 years ago, so >>>>>> probably it was only about 3 years ago that it will have begun >>>>>> appearing in stable distros, if at all. Filesystem passthrough to >>>>>> Linux guests installed in the last couple of years is a useful >>>>>> feature, and I know that for many people that is their only use of >>>>>> KVM, but compared with CIFS' broad support it seems like quite a >>>>>> narrow goal. >>>>> The goal is to have something simple and fast. We can fine-tune 9P to >>>>> align with the Linux VFS structures, making it really little overhead >>>>> (and little headache too). For Windows guests, nothing prevents us to >>>>> expose yet another 9P flavor. That again would be aligned well with >>>>> Windows's VFS and be slim and fast there. >>>>> >>>>> The biggest problem I see with CIFS is that it's a huge beast. There are >>>>> a lot of corner cases where it just doesn't fit in. See my previous mail >>>>> for more details. >>>>> >>>> As Alex mentioned, 9P is chosen for its mere simplicity and easy >>>> adaptability. >>>> NFS and CIFS does not give that flexibility. As we mentioned in the patch >>>> series, we are >>>> already seeing better numbers with 9P. Looking ahead 9P can embed KVM/QEMU >>>> knowledge >>>> to share physical resources like memory/cache between the host and the >>>> guest. >>>> >>>> I think looking into the windows side of 9P client would be great option >>>> too. >>>> The current patch on the mailing list supports .U (unix) protocol and will >>>> be introducing >>>> .L (Linux) variant as we move forward. >>> Hi Mohammed, >>> Please let us know once you decide on where your interest lies. >>> Will be glad to have you on VirtFS (9P) though. :) >>> >>> >>> - JV >>> >> >> It seems the community is more keen on getting 9P support merged than >> getting CIFS supported, and they have made good points to support >> their argument. I'm not sure whether work on this project could fit in >> as a GSoC project and if there is much remaining work that could make >> it fit in that direction. But I'd be glad to volunteer anyway :) > > I was thinking over the wk-end what fits your schedule and your interest > areas. :) > > One thing I can think of is, making NFS server export VirtFS mount on the > guest to > the external world. This works fine now if we enable loose cache option in 9P > mount. > But I think we should identify and make this exports work even otherwise. > Please let me know if this is something that you want to sign up. :) > > Thanks, > JV >
This'd be something interesting to do. I wonder if that would fit in the GSoC timeframe, or whether it'd be a little too short. So how long you'd estimate something like that would take? Regards, Mohammed
