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Diff for /wikisrc/ports/xen/howto.mdwn between versions 1.134 and 1.135

version 1.134, 2016/12/20 21:22:57 version 1.135, 2016/12/21 16:57:10
Line 150  only which command you use, but the comm Line 150  only which command you use, but the comm
 xentools packages provide xm for 3.1, 3.3 and 4.1 and xl for 4.2 and up.  xentools packages provide xm for 3.1, 3.3 and 4.1 and xl for 4.2 and up.
   
 In 4.2, you can choose to use xm by simply changing the ctl_command  In 4.2, you can choose to use xm by simply changing the ctl_command
 variable.  variable and setting xend=YES in rc.conf.
   
 With xl, virtual devices are configured in parallel, which can cause  With xl, virtual devices are configured in parallel, which can cause
 problems if they are written assuming serial operation (e.g., updating  problems if they are written assuming serial operation (e.g., updating
Line 197  work, and an i386 dom0 kernel should in  Line 197  work, and an i386 dom0 kernel should in 
 Xen/dom0 is known to support both i386 and amd64 domUs.  Xen/dom0 is known to support both i386 and amd64 domUs.
   
 i386 dom0 and domU kernels must be PAE (except for an i386 Xen 3.1  i386 dom0 and domU kernels must be PAE (except for an i386 Xen 3.1
 kernel, where one can use non-PAE for dom0 and all domUs); PAE  kernel, where one can use non-PAE for dom0 and all domUs); PAE kernels
 versions are included in the NetBSD default build.  (Note that emacs  are included in the NetBSD default build.  (Note that emacs (at least)
 (at least) fails if run on i386 with PAE when built without, and vice  fails if run on i386 with PAE when built without, and vice versa,
 versa, presumably due to bugs in the undump code.)  presumably due to bugs in the undump code.)
   
 Because of the above, the standard approach is to use NetBSD/amd64 for  Because of the above, the standard approach is to use an amd64 Xen
 the dom0 and therefore an amd64 Xen kernel, and to use PAE kernels for  kernel and NetBSD/amd64 for the dom0.  For domUs, NetBSD/i386 (with
 i386 domUs.  the PAE kernel) and NetBSD/amd64 are in widespread use, and there is
   little to no Xen-specific reason to prefer one over the other.
   
 Note that to use an i386 dom0 with Xen 4.5 or higher, one must build  Note that to use an i386 dom0 with Xen 4.5 or higher, one must build
 an amd64 Xen kernel and install that on the system.  One must also use  (or obtain from pre-built packages) an amd64 Xen kernel and install
 a PAE i386 kernel.  There is no good reason to undertake these  that on the system.  (One must also use a PAE i386 kernel, but this is
 contortions; you should use a NetBSD/amd64 dom0 system.  also required with an i386 Xen kernel.).  Almost no one in the
   NetBSD/Xen community does this, and the standard, well-tested,
   approach is to use an amd64 dom0.
   
   A [posting on
   xen-devel](https://lists.xen.org/archives/html/xen-devel/2012-07/msg00085.html)
   explained that PV system call overhead was higher on amd64, and thus
   there is some notion that i386 guests are faster.  It goes on to
   caution that the total situation is complex and not entirely
   understood. On top of that caution, the post is about Linux, not
   NetBSD.  TODO: Include link to benchmarks, if someone posts them.
   
 Stability  Stability
 ---------  ---------
Line 247  The following table gives status, with t Line 258  The following table gives status, with t
 (generally on the most recent quarterly branch).  The first code is  (generally on the most recent quarterly branch).  The first code is
 "builds" if it builds ok, and "FAIL" for a failure to build.  The  "builds" if it builds ok, and "FAIL" for a failure to build.  The
 second code/date only appears for xenkernel* and is "works" if it runs  second code/date only appears for xenkernel* and is "works" if it runs
 ok as a dom0, and "FAIL" if it won't boot or run a domU.  ok as a dom0 and can support a domU, and "FAIL" if it won't boot or
   run a domU.
   
         xenkernel3 netbsd-6 i386 FAIL 201612          xenkernel3 netbsd-6 i386 FAIL 201612
         xenkernel33 netbsd-6 i386 FAIL 201612          xenkernel33 netbsd-6 i386 FAIL 201612
Line 303  configuration. Line 315  configuration.
   
 For experimenting with Xen, a machine with as little as 1G of RAM and  For experimenting with Xen, a machine with as little as 1G of RAM and
 100G of disk can work.  For running many domUs in productions, far  100G of disk can work.  For running many domUs in productions, far
 more will be needed.  more will be needed; e.g. 4-8G and 1T of disk is reasonable for a
   half-dozen domUs of 512M and 32G each.  Basically, the RAM and disk
   have to be bigger than the sum of the RAM/disk needs of the dom0 and
   all the domUs.
   
 Styles of dom0 operation  Styles of dom0 operation
 ------------------------  ------------------------
Line 390  releasedir/i386/binary/kernel/netbsd-XEN Line 405  releasedir/i386/binary/kernel/netbsd-XEN
 should not use Xen 3.1.)  Both xen and the NetBSD kernel may be (and  should not use Xen 3.1.)  Both xen and the NetBSD kernel may be (and
 typically are) left compressed.  typically are) left compressed.
   
 In a dom0 kernel, kernfs is mandatory for xend to communicate with the  In a dom0, kernfs is mandatory for xend to communicate with the
 kernel, so ensure that /kern is in fstab.  TODO: Say this is default,  kernel, so ensure that /kern is in fstab.  (A standard NetBSD install
 or file a PR and give a reference.  should already mount /kern.)
   
 Because you already installed NetBSD, you have a working boot setup  Because you already installed NetBSD, you have a working boot setup
 with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the  with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the
 beginning of your root file system, /boot present, and likely  beginning of your root file system, have /boot, and likely also
 /boot.cfg.  (If not, fix before continuing!)  /boot.cfg.  (If not, fix before continuing!)
   
 Add a line to to /boot.cfg to boot Xen.  See boot.cfg(5) for an  Add a line to to /boot.cfg to boot Xen.  See boot.cfg(5) for an
Line 441  Using grub (historic) Line 456  Using grub (historic)
   
 Before NetBSD's native bootloader could support Xen, the use of  Before NetBSD's native bootloader could support Xen, the use of
 grub was recommended.  If necessary, see the  grub was recommended.  If necessary, see the
 [old grub information](/ports/xen/howto-grub/).  [old grub information](/ports/xen/howto-grub).
   
 The [HowTo on Installing into  The [HowTo on Installing into
 RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)  RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)
 explains how to set up booting a dom0 with Xen using grub with  explains how to set up booting a dom0 with Xen using grub with
 NetBSD's RAIDframe.  (This is obsolete with the use of NetBSD's native  NetBSD's RAIDframe.  (This is obsolete with the use of NetBSD's native
 boot.)  boot.  Now, just create a system with RAID-1, and alter /boot.cfg as
   described above.)
   
 Configuring Xen  Configuring Xen
 ---------------  ---------------
Removed from v.1.134  
changed lines
  Added in v.1.135

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