Why we use OPAM for XenServer development

Why we use OPAM for XenServer development
https://opam.ocaml.org/blog/opam-in-xenserver/

• manages clusters of Xen hosts with shared storage and networking
• allows running VMs to be migrated between hosts (with or without storage) with minimal downtime
• automatically restarts VMs after host failure (High Availability)
• allows cross-site Disaster Recovery
• simplifies maintainence through Rolling Pool Upgrade
• collects performance statistics for historical analysis and for alerting
• has a full-featured XML-RPC based API, used by clients such as XenCenter, Xen Orchestra, OpenStack and CloudStack

xapi のインストール方法（CentOS6への）なので、メモっておきます。

Conver XVA to VHD

Re: [xs-devel] covert xva to img
https://lists.xenserver.org/sympa/arc/xs-devel/2015-02/msg00078.html

Try something like (on 6.5 and later)
$ xe vdi-export uuid=… filename=foo.vhd format=vhd ?progress

XenServer6.5以降ではできるっぽい。試してないけど。

Hotfix XS65E001 - For XenServer 6.5.0

Hotfix XS65E001 - For XenServer 6.5.0
http://support.citrix.com/article/CTX142060

XenCenterの修正。
GPUタブの修正とかvGPU設定とか、Rolling Pool Upgrade時のStaticIPが失敗するとか、WLBの修正とか。

Power Settings in XenServer 6.5: C-states, Turbo and CPU Frequency Scaling

Power Settings in XenServer 6.5: C-states, Turbo and CPU Frequency Scaling

http://support.citrix.com/article/CTX200390

This article explains changes introduced in XenServer 6.5 to the handling of power settings and describes how users with specific needs can change the configuration.
XenServer's default power settings are optimal for most users, so do not normally need to be modified.
In its default configuration, XenServer 6.5:
* uses all available C-states regardless of BIOS settings,
* uses the "performance" CPU frequency governor for Intel processors and the more power-friendly "ondemand" CPU frequency governor for AMD processors, and
* uses frequency scaling and Turbo mode as controlled by the BIOS settings.
It is recommended to use XenServer's default configuration and to enable OS-controlled frequency scaling and Turbo mode in the BIOS.

えー C-statesの設定戻すのめんどくさい。

ちなみに、XenServer6.2SP1以前は、C-states はDisable推奨というか必須だったはず。