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authorThomas Schwinge <thomas@schwinge.name>2011-03-28 10:30:54 +0200
committerThomas Schwinge <thomas@schwinge.name>2011-03-28 10:30:54 +0200
commit0cd321c45aea93ea9bbf2821c2b81a45a9124f8b (patch)
tree84dc3000069cc9c95ab45cda67cc39bf78471b9c /hurd/running/qemu
parent1049f72d37aa1efc434c96eff42ad522eb331c90 (diff)
Move a bunch of IRC discussion logs to discussion subpages.
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+[[!meta copyright="Copyright © 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free
+Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_documentation]]
+
+# Using Partitions
+
+[[IRC]], #hurd, 2007-07-04.
+
+ <azeem-uni> so, is there a way to use a Debian GNU/Hurd partition
+ (/dev/hda6) with qemu directly?
+ <tschwinge> Don't dare to do that, please.
+ <tschwinge> It will lead to inconsistencies.
+ <tschwinge> Because the Linux kernel thinks that it has complete control
+ over the disk, or something.
+ <tschwinge> In theory you could run something like ``-hda /dev/hda'',
+ having GRUB installed on there to offer you to boot your Hurd system from
+ hda6 and that will even work, but then don't get the idea to stop qemu,
+ mount that partition on your Linux system and restart qemu. That's where
+ I got lots of inconsistencies then, afterwards.
+ <azeem-uni> it's probably the same problem as having that partition
+ mounted, suspending to disk, booting into it in the Hurd, and resume
+ Linux
+ <neal> right
+ <tschwinge> That's a different problem.
+ <tschwinge> Then the partitoon is still mounted.
+ <neal> no, I think it is basically the same problem
+ <tschwinge> The file system stuff is cached in the kernel.
+ <neal> you have data that has not been written to disk yet
+ <tschwinge> Right.
+ <neal> and neither is prepared for the resource to be shared
+ <tschwinge> In the azeem-uni scenarion the data is on the file system layer
+ and in my scenarion it's some disk block caching inside the Linux kernel,
+ I guess.
+ <azeem-uni> anyway, do you guys think if I use -hda /dev/hda and tell Grub
+ to boot off /dev/hda6, that the rest of hda should be fine, right?
+ <azeem-uni> maybe adding -snapshot makes it totally safe
+ <neal> azeem: Should be fine.
+ <tschwinge> Yes.
+
+The problem is actually that the linux block cache doesn't make any consistency
+between /dev/hda and /dev/hda6, so if you give /dev/hda to qemu, qemu writings
+won't be consistent with mounting /dev/hda6 in linux. You can give /dev/hda6
+directly to qemu and it will be fine.