[LHC]虚拟化：LHC 物理志愿者计算的关键

碧城仙

来源：http://www.distributedcomputing.info/news.html
原载：International Science Grid this Week - http://www.isgtw.org/?pid=1002375
标题：Virtualization: Key for LHC physics volunteer computing - 虚拟化：LHC 物理志愿者计算的关键
作者：Ben Segal, CERN, and Seth Bell, iSGTW.
日期：2010年2月24日
概要：an overview of the CernVM software appliance which will allow large-scale Linux-based physics simulation experiment software to use the BOINC computing platform and volunteer computing from Windows PCs

有愿意帮助翻译的，请直接回帖（可以先占座，再翻译或编辑）

zglloo

#因为看标题和虚拟化有关就来尝试下！
虚拟化- LHC 物理志愿者计算的关键
In 2006, the team that built LHC@home was given a challenge by Wolfgang von Rueden, then IT Division Leader at CERN: look at the use of the volunteer computing project BOINC for simulating events of interest in the Large Hadron Collider.
在2006年， LHC@home的艰巨任务由沃尔夫·冯·芮登来领队团队，他曾是CERN IT项目主要负责人： 计算志愿者项目BOINC用于模拟大型强子对撞机引起的兴趣而被关注。

It presented a demanding problem.
对此他提出了苛刻的问题。

The software environments used by the experiments such as ATLAS, ALICE, CMS and LHCb are very large.
该软件在环境实验中使用时，例如ATLAS, ALICE, CMS 和LHCb的数据显得非常巨大。

Furthermore, all LHC physics software development is done under Scientific Linux, whereas most volunteer PCs run under Windows. Porting the large and rapidly changing software is not practical, so another approach was needed.
此外，所有的LHC物理方面的软件都在Scientific Linux下完成开发，尽管绝大多数的PC用户运行在Windows下。移植大型或动态变化的的软件是不切实际的，因此我们寻求另一种解决方案是必要的。

Marrying volunteer computing with the CernVM virtual image management system under development. It would enable the practical use of thousands of volunteer PCs as an additional grid resource to run increased amounts of event simulation for the LHC experiments.
我们正在开发用于志愿计算与CernVM虚拟影像相结合的管理系统。它会使成千上万的志愿者PC的运用于LHC网格实验仿真提升额外资源。

CERN had begun harnessing Volunteer Computing in 2004 to aid the LHC project through the LHC@home system, which allowed CERN accelerator engineers to run intensive simulations to check the  stability of the twin proton beams circulating in the LHC machine.
CERN于2004年LHC@home系统通过志愿计算开始辅助LHC项目，这使CERN加速器的工程师能够对于LHC进行十分细致的模拟，并以此检验LHC机器中双质子束循环的稳定性。

More than 50,000 members of the public volunteered spare cycles of their PCs to carry out these calculations, with their effort managed by the open source BOINC system, part of the well known SETI@home project.
大约5万多市民自愿运用他们的PC来进行这些计算，他们所有的努力归功于开源平台BOINC系统.多数略有耳闻的人们都知晓SETI@home。

BOINC is versatile enough that even mobile phones can do volunteer computing.
仅仅是BOINC通用计算远远不够，甚至手机也可能参与其中

Enter CernVM   进入cernVM
Since then, almost all the effort at CERN around BOINC was and is undertaken by student interns during summer. Two such students surveyed the potential of virtualization for solving the problem.
从那时起，几乎所有的CERN人员都在围绕BOINC的虚拟化而努力这其中还有暑期的实习生。正是这两位实习生调查虚拟化中的问题起到关键。

Instead of sending a ported executable to the volunteer PC, an LHC Linux environment with the exact version of running physics code is sent and executed under a virtual hypervisor. Results were promising, since virtualization entailed only a few percent of CPU overhead.
这可不是单纯发送可执行到志愿者的PC上，而是将所有的LHC Linux环境及准确版本都运行在物理代码发送至虚拟管理系统下执行（virtual hypervisor），希望结果行得通，自从虚拟化的涉及cpu只有一小部分开销。

However, fresh challenges came about, due to the very large size of the virtual image required to contain all the LHC experiment software packages (about 8-10 gigabytes). Further complicating things, there were frequent changes in packages, with each change requiring a full image reload.
然而，新的问题是由于虚拟镜像环境中包含LHC的实验包非常之巨大（约有8-10GB左右[gigabytes=GB]）。更加复杂的是，其中有频繁改变的数据包，每一个变化都需要完整的镜像重新加载。

CernVM, launched in 2008 by Predrag Buncic, offered a general solution to the problem of virtual image management for physics computing. Instead of loading each running virtual machine with the full image containing all the code and libraries for an LHC experiment, only a basic “thin appliance” of about 100 megabytes is loaded initially, and further image increments are loaded as needed. Updates to images are made automatically by the CernVM system, which keeps up-to-date versions of all image modules in a repository for each supported LHC experiment. The resulting working images are typically less than 1 gigabyte in size and are cached by the virtual machines, minimizing access to the CernVM repository until changes appear.


Since 2008, further students and volunteers have produced a working prototype of a combined BOINC-CernVM system. Further work by the CernVM team has successfully linked CernVM to two of the LHC experiments' job production systems (ATLAS’s PanDA and ALICE’s AliEn). This allows the ATLAS and ALICE experiments to access CernVM “Clouds” without changing their production scripts or procedures.


Exploiting all this work would therefore offer “Volunteer Clouds” of BOINC PCs to be harnessed as an additional resource of processing power to assist the LHC experiments. It was presented at the Advanced Computing and Analysis Techniques in Physics Research conference in Jaipur, India, yesterday (February 23, 2010).
运用这些“志愿云计算”工作都将使得BOINC电脑作为额外的计算资源来协助LHC的实验。它是在先进的计算与分析技术在物理学研究,在昨日位于印度斋浦尔(2月23日,2010年)。

—Ben Segal, CERN, and Seth Bell, iSGTW. For more, see the entry on Indico
—本•席格，CERN，和贝尔•塞斯，iSGTW，有关详细信息项，请到Indico

未完待续

昂宿星团人

回复 2# zglloo

CERN于2004年LHC@home系统通过志愿计算开始辅助LHC项目，而CERN加速器的工程师想通过LHC深入了解模拟双质子束在稳定的LHC机器中循环。
    个人认为可以译成“这使CERN加速器的工程师能够对于LHC进行十分细致的模拟，并以此检验LHC机器中双质子束循环的稳定性。”

另外，感觉最后一段中“public”译为“市民”有些别扭，不过我也想不出来有什么更合适的词

acp134

昂宿星团人 发表于 2010-8-11 19:54
回复 2# zglloo

CERN于2004年LHC@home系统通过志愿计算开始辅助LHC项目，而CERN加速器的工程师想通过LHC ...

不好意思挖个坟……
Public翻译成公众比较好

昂宿星团人

倒数二、三段补完：

CernVM, launched in 2008 by Predrag Buncic, offered a general solution to the problem of virtual image management for physics computing. Instead of loading each running virtual machine with the full image containing all the code and libraries for an LHC experiment, only a basic “thin appliance” of about 100 megabytes is loaded initially, and further image increments are loaded as needed. Updates to images are made automatically by the CernVM system, which keeps up-to-date versions of all image modules in a repository for each supported LHC experiment. The resulting working images are typically less than 1 gigabyte in size and are cached by the virtual machines, minimizing access to the CernVM repository until changes appear.
CernVM，由Predrag Buncic于2008年开发完成。它为物理计算提供了一个虚拟的镜像管理问题的整体解决方案。之前的做法是在所有运行中的虚拟机上都加载包含全部LHC实验用代码和库的镜像，现在CrenVM只加载一些基础的、大概只有100Mb左右的“十分薄的程序”，而更进一步的镜像内容将会被按需加载。镜像内容的更新由CernVM系统自动进行，这保证了其管理的每个LHC实验对应的库中都存有最新版的镜像。结果反馈镜像一般来说都会小于1Gb，并由虚拟机负责缓存，在出现变化前，其与CernVM的库间的通信会保持最小量。


Since 2008, further students and volunteers have produced a working prototype of a combined BOINC-CernVM system. Further work by the CernVM team has successfully linked CernVM to two of the LHC experiments' job production systems (ATLAS’s PanDA and ALICE’s AliEn). This allows the ATLAS and ALICE experiments to access CernVM “Clouds” without changing their production scripts or procedures.
从2008年开始，有研究者与志愿者开始提出一种CernVM与BOINC的联合系统的工作原型。进一步的工作由CernVM团队完成：他们成功地将CernVM连接到了LHC实验的工作产品系统上（ATLAS’s PanDA and ALICE’s AliEn）。这使ATLAS和ALICE实验得以在不改变其产品脚本的情况下同CernVM“云”通信。

昂宿星团人

已搬运
http://www.equn.com/wiki/%E8%99% ... 4%E5%85%B3%E9%94%AE