[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] VBD extents
> So in XEN 2.0 is VBD grow/shrink used? Yes, Xend uses them when creating a VBD. Xend first creates a given VBD, which starts off with zero size. Xend then adds exactly one segment to the VBD using a grow message - this segment describes the device the VBD is mapping. Shrink messages probably aren't used anywhere at all. > 0). If indeed these messages will eventually be removed, i take it XEND > will need to send a message to blkback identifying the disk device driver That sounds right - basically just removing the vestiges of multi-extent support in blkback so that each VBD has exactly one extent. Cheers Mark > Eric > > Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx> wrote: > > Can anyone tell me what exactly the VBD extents are used for > > in the XEN back-end block device driver? It almost looks > > like each virtual disk is made up of multiple physical drives > > if I read the code correctly (for each VBD grow message > > received by blkback, it opens a device and retreives various > > info such as its size). > > The extent stuff is left over from Xen 1.2, where we effectively had to > do our own version of LVM inside Xen. We'd like to give the code a > spring clean and do away with the grow/srink control messages > altogether. At the same time it would be sensible to add support for > multiple blk rings, and possibly the ability to 'tunnel' certain ioctls > e.g. eject CD. > > Ian > > > ------------------------------------------------------- > The SF.Net email is sponsored by: Beat the post-holiday blues > Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. > It's fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/xen-devel > > > --------------------------------- > Do you Yahoo!? > Yahoo! Mail - 250MB free storage. Do more. Manage less. ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/xen-devel
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