93 lines
3.2 KiB
Diff
93 lines
3.2 KiB
Diff
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---
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docs/misc/xenpaging.txt | 66 +++++++++++++++++++++++++++++-------------------
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1 file changed, 40 insertions(+), 26 deletions(-)
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Index: xen-4.1.2-testing/docs/misc/xenpaging.txt
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===================================================================
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--- xen-4.1.2-testing.orig/docs/misc/xenpaging.txt
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+++ xen-4.1.2-testing/docs/misc/xenpaging.txt
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@@ -1,8 +1,6 @@
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Warning:
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The xenpaging code is new and not fully debugged.
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-Usage of xenpaging can crash Xen or cause severe data corruption in the
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-guest memory and its filesystems!
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Description:
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@@ -14,34 +12,50 @@ than physically available on the host.
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Usage:
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-Once the guest is running, run xenpaging with the guest_id and the
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-number of pages to page-out:
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+To enable xenpaging for a guest add the option 'actmem=' to the guests
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+config file and run 'xm new <vm_config_file>' to make the changes
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+active. actmem= takes the amount of memory in MB which a guest is
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+allowed to use at a given time. Everything above this limit will be
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+paged out. This paging is transparent to the guest.
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+
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+Example:
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+ memory=4096
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+ actmem=1024
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+In this example a guest gets the impression it has 4GB of memory and
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+the guest OS has to configure itself for this amount of memory. But
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+xenpaging will page-out 3072MB, leaving only 1024MB active at a time.
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+
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+At runtime the configured value of actmem= can be changed with the "xm
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+mem-swap-target" command.
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+ xm mem-swap-target <domain_name> 512
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+
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+Additional cmdline options for the xenpaging binary can be specified
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+with the xenpaging_extra= config file option:
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+
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+ xenpaging_extra=[ '-f', '/dev/shm/pagefile-guest_name', '-v' ]
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+
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+To get a list of available options, run /usr/lib/xen/bin/xenpaging -h:
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+
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+ xenpaging [options] -f <pagefile> -d <domain_id>
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+
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+options:
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+ -d <domid> --domain=<domid> numerical domain_id of guest. This option is required.
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+ -f <file> --pagefile=<file> pagefile to use. This option is required.
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+ -m <max_memkb> --max_memkb=<max_memkb> maximum amount of memory to handle.
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+ -r <num> --mru_size=<num> number of paged-in pages to keep in memory.
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+ -v --verbose enable debug output.
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+ -h --help this output.
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+
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+
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+Caveats:
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+Live migration with a paged guest does currently not work, the guest
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+will crash once it starts on the target host. As a workaround stop
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+paging before starting the migration:
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- chdir /var/lib/xen/xenpaging
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- xenpaging <guest_id> <number_of_pages>
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-
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-To obtain the guest_id, run 'xm list'.
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-xenpaging will write the pagefile to the current directory.
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-Example with 128MB pagefile on guest 1:
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-
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- xenpaging 1 32768
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-
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-Caution: stopping xenpaging manually will cause the guest to stall or
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-crash because the paged-out memory is not written back into the guest!
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-
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-After a reboot of a guest, its guest_id changes, the current xenpaging
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-binary has no target anymore. To automate restarting of xenpaging after
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-guest reboot, specify the number if pages in the guest configuration
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-file /etc/xen/vm/<guest_name>:
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-
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-xenpaging=32768
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-
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-Redo the guest with 'xm create /etc/xen/vm/<guest_name>' to activate the
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-changes.
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+xm mem-swap-target <dom_name> 0 && xm migrate -l <dom_name> <remote_host>
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Todo:
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-- implement stopping of xenpaging
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- implement/test live migration
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