Hi Alok, On 05/24/10 08:46 PM, Alok Aggarwal wrote: > Hi Darren, > > On Mon, 24 May 2010, Darren Kenny wrote: > >> Hmm, does read a little weird ;) >> >> What I am trying to say here is that because the DOC is the center point for >> all data regarding an install, it is then possible to use this fact to >> generate an XML manifest - and then later, if using this manifest re-create >> the DOC from the manifest to re-perform an install. > > I'm still confused. Serializing the DOC data into XML and then > snapshotting it should allow us to later re-create the DOC > and re-perform the install. Is that not enough? If it is, then > I'm having trouble seeing the role this XML manifest plays.
I think that you're confusing two things here: 1) Snapshot and Roll-back This is being dong using a *non-XML* format where the *whole* cache is "pickled" (serialized) to disk, and read back in. This is not intended to have any direct relationship to an XML Manifest, but only to allow the Application to be able to perform a roll-back if required. 2) XML Manifest Import and Generation A requirement of the DOC was that it would be able to generate an XML Manifest (be it DC or AI, or other). A purpose that I see for a generated XML Manifest is where, for example, you did a GUI install, and at the end asked it to generate an XML Manifest based on the install you just did. In theory then, this same manifest, could then be used for an AI install later, unattended, so you can thus have a possible means for replicating an install based on an interactive install... A natural extension of this is that the DOC can also import the XML nodes that make up an XML Manifest - this will be utilised as part of the ManifestParser implementation, and as such will re-populate, although only partially, the DOC. What's important here is that the XML Manifest is not, and never will be, the complete contents of the DOC - people can store a lot more information in the DOC, and avoid being written to a manifest by implementing to_xml() such that it returns None. For DC to resume, it will need to first load a snapshot to resume from (to get correct information about completed checkpoints) and merge in the XML Manifest checkpoints. Does that make it any clearer? Thanks, Darren. _______________________________________________ caiman-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/caiman-discuss
