190 lines
3.5 KiB
HTML
190 lines
3.5 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>How drive linking is implemented</TITLE
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
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REL="HOME"
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TITLE="EVMS User Guide"
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HREF="index.html"><LINK
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TITLE="Creating drive links"
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HREF="evmscreatedrivelinking.html"><LINK
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REL="PREVIOUS"
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TITLE="What is drive linking?"
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HREF="whatisdrivelinking.html"><LINK
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REL="NEXT"
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TITLE="Creating a drive link"
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HREF="x1453.html"></HEAD
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>Prev</A
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>Chapter 10. Creating drive links</TD
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WIDTH="10%"
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VALIGN="bottom"
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><H1
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CLASS="sect1"
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><A
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NAME="howimp"
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></A
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>10.2. How drive linking is implemented</H1
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><P
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>The drive link plug-in consumes storage objects, called link
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objects, which produce a larger drive link object whose address space spans
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the link objects.
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The drive link plug-in knows how to assemble the link objects so as to
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create the exact same address space every time.
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The information required to do this is kept on each link child as persistent
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drive-link metadata.
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During discovery, the drive link plug-in inspects each known storage
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object for this metadata.
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The presence of this metadata identifies the storage object as a link object.
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The information contained in the metadata is sufficient to:</P
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><P
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></P
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><UL
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><LI
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><P
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>Identify the link object itself.</P
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></LI
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><LI
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><P
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>Identify the drive link storage object that the link object belongs to.
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</P
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></LI
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><LI
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><P
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>Identify all link objects belonging to the drive link storage.
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object</P
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></LI
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><LI
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><P
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>Establish the order in which to combine the child link objects.</P
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></LI
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></UL
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><P
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>If any link objects are missing at the conclusion of the discovery
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process, the drive link storage object contains gaps where the missing
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link objects occur.
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In such cases, the drive link plug-in attempts to fill in the gap with a
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substitute link object and construct the drive link storage object in
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read-only mode, which allows for recovery action.
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The missing object might reside on removable storage that has been removed or
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perhaps a lower layer plug-in failed to produce the missing object.
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Whatever the reason, a read-only drive link storage object, together
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logging errors, help you take the appropriate actions to recover the drive link.
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</P
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HREF="whatisdrivelinking.html"
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ACCESSKEY="P"
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>Prev</A
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>Next</A
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>What is drive linking?</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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>Up</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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>Creating a drive link</TD
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></TR
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></TABLE
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> |