On Sat, 10 Apr 2021 at 16:42, Tomas By <to...@basun.net> wrote: > > On Sat, 10 Apr 2021 17:24:03 +0200, Peter Maydell wrote: > > If you are trying to have multiple guests running simultaneously > > which are all using the same disk, then that *is* a distributed > > filesystem setup (multiple clients, one disk). > > Well... > > "GlusterFS aggregates various storage servers over Ethernet or > Infiniband RDMA interconnect into one large parallel network file > system."
Yes, but there's no DOS support for it, is there? (Also, it's a network filesystem, not a thing that goes on a disk.) > > What that message > > is saying is effectively that you have two choices: > > (1) [...] > > (2) accept that you are running a multi-machine cluster which is > > sharing a disk and use a filesystem type and guest setup that > > works that way > > Okay, #2 sounds fine... ...except that it's probably a lot of work and might not even be possible if your guest is DOS rather than Linux. > > For DOS in particular, I don't expect it is likely to have support > > for multi-cluster disk use. > > I'm not sure I follow the last bit there, but sharing a disk is what > SHARE.EXE is for: > > "Locking files became necessary when MS-DOS began allowing files to be > accessed simultaneously by multiple programs, either through > multitasking or networking." No, SHARE.EXE is just "if you have a networked fileserver, then you need this". It doesn't help you in getting or setting up that networked fileserver in the first place. > > I suppose in theory you could set it up the way you'd have set up > > a shared disk in hardware back in the day: have a file server > > and get all the DOS guests to use it as a networked disk. > > Well, you did not need a file server, only a network. > > I think it worked the same on one single machine when Windows (or > OS/2) started to allow multi-tasking. > > So how do I set this up under QEMU? Which format for the shared disk? This is a guest configuration question. There is no magic "tell QEMU to use this format for a shared disk image and it will all work" option. You'd need to run *one* guest connected to the disk, and have it serve access to that disk over the network, that your other guests access only as a network drive. thanks -- PMM
