On Jan 8, 2012 12:43 AM, "Michael Mol" <mike...@gmail.com> wrote: > > On Sat, Jan 7, 2012 at 11:35 AM, Pandu Poluan <pa...@poluan.info> wrote: > > On Jan 7, 2012 8:44 PM, "victor romanchuk" <r...@persimplex.net> wrote: > >> > >> Konstantinos Agouros wrote, at 01/07/2012 03:51 PM: > >> > since xen got into the mainstream kernel the way to go is to use > >> > gentoo-sources for dom0 and the domUs. However the blktap modules are > >> > not > >> > there. Is there any way to get this to work? > >> > >> blktap drivers were excluded from kernel mainline since 3.x, these two > >> threads > >> from xen-users mailing list might put some light in that context: > >> > >> > >> http://old-list-archives.xen.org/archives/html/xen-users/2011-07/msg00637.html > >> > >> http://old-list-archives.xen.org/archives/html/xen-users/2011-10/msg00065.html > >> > >> the latest sys-kernel/xen-sources containing working blktap (not blktap2) > >> is > >> 2.6.38 (this is buggy from my point of view; i'm still sitting on > >> 2.6.34-r5 for > >> production installations) > >> > > > > Can someone shed a light on the importance of blktap, i.e., why one would > > want to use it when -- as someone explained in the first email thread you > > gave -- blkfront+blkend is enough for paravirtualization? > > Reading through the linked threads, it sounds like the benefit stems > from being able to shim things in between the front and back ends. > > You might want that for any number of reasons: > * a block encryption layer > * a metering layer > * a read/write masking layer > * an intercept to have the block device exist on (or be mirrored to) > on another system. > > etc. >
Ah yes, of course. One of the threads also mentioned that blktap might be better implemented in userspace. Rgds,
