20:54 How would you compress your MySQL Backup (7715 Bytes) » MySQL Performance Blog

Backing up MySQL Database most people compress them - which can make a good sense in terms of backup and recovery speed as well as space needed or be a serious bottleneck depending on circumstances and approach used.

First I should mention this question mainly arises for medium and large size databases - for databases below 100GB in size compression performance is usually not the problem (though backup impact on server performance may well be).

We also assume backup is done on physical level here (cold backup, slave backup, innodb hot backup or snapshot backup) as this is only way practical at this point for databases of decent size.

Two important compression questions you need to decide for backup is where to do compression (on the source or target server if you backup over network) and which compression software to use.

Compression on source server is most typical approach and it is great, though it takes extra CPU resources on the source server in additional to IO resources which may not be available, especially for CPU bound MySQL Load. The benefit in this case is less space requirement if you’re keeping the local copy as well as less network bandwidth requirements in case you’re backing up to network storage.

Compression on the destination server offloads source server (though it may run our of CPU itself, if it is target for multiple backups, plus there are higher network bandwidth requirements to transfer uncompressed backup.

What is about compression tool ? The classical tool used for backup compression is gzip - it exists almost everywhere, it is stable and relatively fast.

In many cases however it is not fast enough and becomes the bottleneck for all the backup process.

Recently I did a little benchmark compressing 1GB binlog file with GZIP (compression done from OS cache and redirected to /dev/null so we only measure compression speed). On the test box with Intel(R) Core(TM)2 Duo CPU E4500 @ 2.20GHz CPU. GZIP would compress this file in
48 seconds (with default options) resulting in 260MB compressed file. This gives us compression speed of about 21MB/sec - clearly much less than even single SATA hard drive can read sequentially. This file when will take about 10 seconds to decompress, meaning source file will be read at 26MB/sec to do decompression - this is again much less than hard drive sequential read performance, though the fact this gives us about 100MB/sec of uncompressed data writing is more of the issue.

Such performance also means if your goal is faster local network transfer default GZIP compression will not speed things up on the standard point to point 1Gbit network connection.

If we try gzip -1 to get fastest compression we get the same file compressed to 320MB in 27 seconds. This gives us 37MB/sec which is a lot better but still not quite enough. Also note the serious leap in compressed file size. Though in this example we used MySQL binary log file which often contains plenty of similar events, which could be the reason for so large size difference based on compression ratio. The decompression takes about same 10 seconds which gives about 32MB/sec of archive read speed and same 100MB/sec of uncompressed data.

Do we have any faster alternatives to GZIP ? There are actually quite a few but I like LZO which I was playing with since later 1990’s and which is rather active project. There is also GZIP like command like compressor using LZO library called LZOP which makes it easy drop in replacement.
I got LZOP binary which was built against LZO 1.0, more resent version 2.0 promises further performance improvements especially on 64bit systems.

With LZO default compression file compressed in 10.5 seconds and resulted in 390MB compressed file, this gives us 97MB/sec compression speed which is good enough to compress all data you can read from single drive. The file decompresses in 3.7 seconds which gives 105MB/sec read speed from archive media and 276MB/sec write speed to the hard drive - this means restoring from backup compressed with LZO will often be as fast or faster as from not compressed one.

With LZO there is also “-1″ option for even faster compression which had rather interesting results. The file compressed in 10.0 seconds (102MB/sec) and was 385MB in size - so this lower compression rate actually compressed this a bit better while being about 5% faster. The decompression speed was about the same. I’m sure the results may change based on the data being compressed but it looks like LZO uses relatively fast compression by default already.

With real server grade CPU deployment the performance should be even better, meaning you should get over +-100MB/second you can pass through 1Gbit ethernet, meaning you actually can use LZO compression for faster data transfer between the boxes (ie together with netcat)

Now as in my benchmarks there is also overhead of reading (from file cache) and piping to the /dev/null which are constant the true difference in compression speed is even larger, though as most of backup operations will need reading and writing anyway they come with this static overhead naturally added.

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20:01 抢修 (839 Bytes) » Fenng's shared items in Google Reader

一大早的就收到告警短信，在上班路上，也没法处理，以为是那个鸟地方的机器又被人DOS了才不通的。

到了单位，几经了解，原来是光缆被挖断了，乡下那个鸟地方的4对光缆断了两对，电信已经去抢修了。

到9点多，实在是被电话骚扰受不了了，出发去机房，准备把受影响的交换机接到不受影响的下面，先用着。于是过去以后把两台交换机连起来，内部起OSPF，出去仍然走静态路由，发布到OSPF里，让人把大网上进来的路由同时指向两个上联口。搞定。

回来后，说光缆修好了，也就这样先跑着了。从断到修好光缆，4个多小时。

...

19:01 ORA-7445(evaopn2)错误 (533 Bytes) » yangtingkun

在alert文件中发现这个ORA-7445错误，而且错误可以重现。在Oracle 9204 for Solaris下执行下面的SQL报错：SQL> SELECT COUNT(*) 2 FROM 3 ( 4 SELECT A.ID,C.PLAT_NAME PROVINCENAME, A.PROJECT_NAME, 5 DECODE(A.REPORT_TYPE,'1','BUYER','2','ORG','3','OTHER') REPORT_TYPE, 6 A.LINKER_NAME,A.MOBILE, 7 SUM(B.MONEY) MONEY,A.MONEY_REMARK 8 FROM AUD_PROJECT A LEFT JOIN PLT_PLAT D 9 ON D.ID = A.CITY_ID 10 INNER JOIN AUD_PROJECT_ITEM B 11 ON A.ID = B.PROJECT_ID 12 INNER JOIN PLT_PLAT C 13 ON A.PLAT_ID = C.ID 14 GROUP ...

19:01 ORA-7445(evaopn2)错误 (533 Bytes) » yangtingkun

在alert文件中发现这个ORA-7445错误，而且错误可以重现。在Oracle 9204 for Solaris下执行下面的SQL报错：SQL> SELECT COUNT(*) 2 FROM 3 ( 4 SELECT A.ID,C.PLAT_NAME PROVINCENAME, A.PROJECT_NAME, 5 DECODE(A.REPORT_TYPE,'1','BUYER','2','ORG','3','OTHER') REPORT_TYPE, 6 A.LINKER_NAME,A.MOBILE, 7 SUM(B.MONEY) MONEY,A.MONEY_REMARK 8 FROM AUD_PROJECT A LEFT JOIN PLT_PLAT D 9 ON D.ID = A.CITY_ID 10 INNER JOIN AUD_PROJECT_ITEM B 11 ON A.ID = B.PROJECT_ID 12 INNER JOIN PLT_PLAT C 13 ON A.PLAT_ID = C.ID 14 GROUP ...

19:01 ANY Types, Pipelined Table Functions, Dynamic SQL and Pivot (3185 Bytes) » Eddie Awad's Blog

Amazing what you can do with ANYTYPE, ANYDATA, ANYDATASET, DBMS_TYPES, DBMS_SQL and pipelined table functions implemented using the interface approach. You can end up with a dynamic sql mashup like you’ve never seen before, and pivot like you’ve never pivoted before. Of course, if you’re on Oracle DB 10g or below, you can never pivot like this.

---
Related Articles at Eddie Awad's Blog:

18:53 大徐，准备好了吗？ (3130 Bytes) » Fenng's shared items in Google Reader

虽然是临时的决定，但经过了仔细的思考，和很多人做了很多次的沟通，决定换个工作环境。每一次辞职，都不是简简单单几句话可以说清楚原因的，都会是一个综合的结果，这次也不例外。以我的计划，今年没准备换工作，我打算踏踏实实的把婚结了以后再考虑工作的事。事实证明，我也完全可以在雅虎继续工作下去。虽然大环境有问题，但是我所在的团队很好，同事很好，我也还有很多需要学习的东西。但最终我还是做出了离开的决定，这个绝对对于年近30岁的我来说，很重要。

这时候换工作要考虑的比几年前要多很多，但当我把机会和风险列出来的时候，一下子事情就变的很清楚了，做这个决定也就简单了。用俗话讲，新的环境“钱多”、“家近”、“活儿少”这三样都占上了。如果仔细考虑的话，新的环境资源很好、也更有机会。目前新的环境还说不太清楚，但有一点是明确的，和无线有关系。2年前的时候我开始思考自己的职业发展，那个时候我觉得有2条路是我希望的，一是无线，二是游戏。我们每个人都知道，无线互联网服务在未来会是多厉害，随着网络基础设施、终端设备的进步，随着人类的欲望的不断扩大，无线互联网服务会超过有线互联网。

其实做游戏现在也有很大的机会，这个机会就是网页游戏。游戏是个很深的行业，这个行当不太容易干，对于干了好几年web项目的我来说，入行不太容易。但好在做产品经理对心理学、需求分析等东西比较在意，做事情也比较有逻辑性。我觉的对于web产品经理来说，网页游戏是个机会。2000年，很多晚上我都是坐在电脑前，喝着茶，写着C程序。这时候我仍然有以后做游戏的梦想，我想做游戏开发，因为那个时候觉得游戏这个东西最有意思。哈哈，不过我自己很少玩游戏。

除了钱多、家近、活儿少、有资源、有机会以外，我还有补课的想法。我一直对手机终端、无线业务没有什么了解，对于我来说，这次换环境也是补课的一个机会。我相信在这里至多呆上2年，我能够成为一个相对来说的明白人，这对我未来长远的职业发展无疑是非常有用的。

好长时间没写blog了，其实一直想写一篇，题目“大徐，准备好了吗？”也想了好长时间。换了环境，压力无疑增加了一些，需要适应很多变化。新的公司、新的团队、新的同事、新的习惯、新的方式、新的语言这些都要适应。好在我的心理年龄还很年轻，我还能拼命的干，还能暂时不求回报的付出。外在环境虽然混乱，好在我心里还明白，我知道我应该怎么做，应该学什么。

我知道我准备好了，大家祝福我吧！

17:31 when others then null, redux (3344 Bytes) » The Tom Kyte Blog

It keeps happening.

Over and over it keeps happening.

Here is case 124,215,412,523 for your review.

The user writes me:

... I have a situation where I have started receiving the 'Cursor is Closed' SQLException from a stored procedure, say, SP_A, suddenly for last 5-6 weeks, since 2nd week of March. This happens only intermittently. If I take the same parameters and execute the sp again after a few minutes after getting the error, it does not generate the error and returns expected results back.

...

Additional details as requested:

what ora-xxxx error are you getting

Unfortunately, it does not generate an ORA-???? error. I know that many a times, the 'Cursor is Closed' error is a coding issue, but in this case, that is not the case. I cannot create this error at will, I have not been able to create the error in our development or user acceptance environment. Even in production, I cannot recreate it with same parameters that have generated the error.

...

The reason I think this could be oracle memory issue is that we very recently moved from 9i to 10g RAC. This application - java code and stored procedures - have been working for about 5 to 6 years now. Even the errors of Cursor is closed we receive are not consistent i.e. The parameters that generate the error now will work with exact same code a few minutes later.

...

Ok, here they are - they say "there is no ora-xxxx error, Oracle is just closing cursors on us - no fair. We know this cannot be a bug in our code, this is a bug in Oracle.

The story ALWAYS goes that way. I just finally gave up... closed the question. They followed up:

What was found that SP_A had exception clause of WHEN OTHERS that was masking the actual error.
When we removed that error, this is the error we see

ORA-04068: existing state of packages has been discarded
ORA-04065: not executed, altered or dropped stored procedure "SP_A"
ORA-06508: PL/SQL: could not find program unit being called: "SP_A"
ORA-06512: at "SP_B", line 317
ORA-06512: at line 1

This is what has been happening intermittently ( we just did not know, because the way the sp was
coded and the java code interacted with returned parameters, it manifested into Cursor Closed Error
).

and now they want "insight" into why this is happening....

Remember everyone, everyone remember, keep in mind:

When others not followed by RAISE or RAISE_APPLICATION_ERROR is almost certainly, with 99.999999999% degree of accuracy, a bug in your developed code. Just say "no" to when others not followed by raise or raise_application_error!

http://www.oracle.com/technology/oramag/oracle/07-jul/o47asktom.html

15:02 Interview with Product Manager Todd Jackson on Gmail Labs (1449 Bytes) » Fenng's shared items in Google Reader

Steve Gillmor and I spoke with Gmail product manager Todd Jackson for a few minutes today following their announcement of Gmail Labs. See our real time notes here for more details.

Crunch Network: MobileCrunch Mobile Gadgets and Applications, Delivered Daily.

10:11 Advanced Oracle Troubleshooting Guide, Part 5: Sampling V$ stuff with WaitProf. Really fast. Using SQL! (1 Bytes) » Tanel Poder's blog: Core IT for geeks and pros

09:02 Advert - New Book (1 Bytes) » Oracle Scratchpad

08:41 Oracle Database 11g Common Background Processes (218 Bytes) » DBASupport

To understand Oracle background processes is to understand how Oracle works--offering opportunity to tune effectively. Learn about the processes that are typically running after a fresh, common, and basic installation.

07:56 Amazon.cn BUG (296 Bytes) » Uploads from dbanotes

dbanotes posted a photo:

06:23 Installing/Configuring/Caching Django on your Linux server (7276 Bytes) » Red Hat Magazine

by Steve “Ashcrow” Milner and Anderson Silva

In today’s world, web development is all about turnaround. Businesses want to maximize production outcome while minimizing development and production time. Small, lean development teams are increasingly becoming the normal large development departments. Enter Django: a popular Python web framework that invokes the RWAD (rapid web application development) and DRY (don’t repeat yourself) principles with clean, pragmatic design.

This article is not about teaching you how to program in Python, nor how to use the Django framework. It’s about showing how to promote your Django applications onto an existing Apache or Lighttpd environment.

We will conclude with a simple way that you can improve the performance of your Django application by using caching to speed up access time. This article also assumes that you are running Fedora as your web application server, but all the packages mentioned in this article are also available under the Extra Packages for Enterprise Linux repository , which means these instructions should also be valid under Red Hat Enterprise Linux or CentOS servers.

What you need

You must have Django installed:

# yum install Django

If you want to serve Django apps under Apache:

# yum install httpd
# yum install mod_python

If you want to serve Django apps under Lighttpd:

# yum install lighttpd
# yum install lighttpd-fastcgi
# yum install python-flup

Installing memcached to ’speed up’ Django apps:

# yum install memcached
# yum install python-memcached

Starting a new Django project

1. Create a development workspace.

$ mkdir -p $LOCATION_TO_YOUR_DEV_AREA
$ cd $LOCATION_TO_YOUR_DEV_AREA

2. Start a new base Django project. This creates the boiler plate project structure.

$ django-admin.py startproject my_app

3. Start the Django development web server on port 8080 (or whatever other port you’d like).

Note: The development web server is just for testing and verification. Do not use it as a production application server!

$ python manage.py runserver 8080

4. Run your Django project under Apache with mod_python by enabling mod_python on httpd.conf (/etc/httpd/conf/httpd.conf).

After installing mod_python, a file called python.conf should already be placed in /etc/httpd/conf.d/, which enables mod_python on your system.

5. Create virtual hosts by creating a new file at /etc/httpd/conf.d/myapp.conf.

 

    DocumentRoot /var/www/html/
    ServerName your_domain_name
    ErrorLog logs/my_app-error.log
    CustomLog logs/my_app-access_log common 

    my_app/">
        SetHandler python-program
        PythonHandler django.core.handlers.modpython
        SetEnv DJANGO_SETTINGS_MODULE my_app.settings
        PythonDebug On
        PythonPath “[’/var/www/django/’] + sys.path”

Running your Django project under Lighthttpd with fastcgi

The first thing you must do is start up your FastCGI server.

./manage.py runfcgi method=prefork socket=/var/www/myapp.sock pidfile=django_myapp.pid

Then modify your lighttpd.conf file to use the FastCGI server.

server.document-root = "/var/www/django/"
fastcgi.server = (
    "/my_app.fcgi" => (
        "main" => (
            # Use host / port instead of socket for TCP fastcgi
            # "host" => "127.0.0.1",
            # "port" => 3033,
            "socket" => "/var/www/my_app.sock",
            "check-local" => "disable",
        )
    ),
)
alias.url = (
    "/media/" => "/var/www/django/media/",
)

url.rewrite-once = (
    "^(/media.*)$" => "$1",
    "^/favicon.ico$" => "/media/favicon.ico",
    "^(/.*)$" => "/my_app.fcgi$1",
)

Setting up caching in Django

Django has many different caching backends, including database, memory, filesystem, and the ever popular memcached. According to http://www.danga.com/memcached/, memcached is “a high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.” It’s used by high traffic sites such as Slashdot and Wikipedia. This makes it a prime candidate for caching in your cool new web app.

First, verify that memcached is running using the memcached’s init script.

$ /etc/init.d/memcached status
memcached (pid 6771) is running...

If it’s not running, you can manually start it.

$ /sbin/service memcached start

If you want to make sure it will automatically start every time after a reboot:

$ /sbin/chkconfig --level 35 memcached on

Now that you have verified that memcached is running, you will want to tell your Django application to use memcached as it’s caching backend. You can do this by adding a CACHE_BACKEND entry to your settings.py file.

CACHE_BACKEND = 'memcached://127.0.0.1:11211/'

The format is “backend://host:port/” or “backend:///path” depending on the backend chosen. Since we are using memcached, we have the option to run multiple daemons on different servers and share the cache across multiple machines. If you want to do this all you must do is add in the servers:port combinations in the CACHE_BACKEND and separate them by semicolons. In this example we share the cache across three different memcached servers:

CACHE_BACKEND = 'memcached://127.0.0.1:11211;192.168.0.10:11211;192.168.0.11/'

For more information on the different types of caching that can be performed in the Django framework, please refer to their official documentation.

06:12 使用kudzu命令查看网卡型号 (4009 Bytes) » Oracle Life

©作者：eygle 发布在 eygle.com

kudzu 是Linux下检测硬件变化的命令，这个命令可以用于检查系统中网卡的型号等信息：

kudzu(1) kudzu(1)

NAME
kudzu - detects and configures new and/or changed hardware on a system

SYNOPSIS
kudzu

DESCRIPTION
kudzu detects and configures new and/or changed hardware on a system.
When started, kudzu detects the current hardware, and checks it against
a database stored in /etc/sysconfig/hwconf, if one exists. It then
determines if any hardware has been added or removed from the system.
If so, it gives the users the opportunity to configure any added hard-
ware, and unconfigure any removed hardware. It then updates the
database in /etc/sysconfig/hwconf.

If no previous database exists, kudzu attempts to determine what
devices have already been configured, by looking at /etc/modules.conf,
/etc/sysconfig/network-scripts/, and /etc/X11/XF86Config.

以下是这个命令执行的输出示例：

[root@wapdbrac1 ~]# kudzu --probe --class=network
-
class: NETWORK
bus: PCI
detached: 0
device: eth1
driver: bnx2
desc: "Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet"
network.hwaddr: 00:1B:78:97:E4:EA
vendorId: 14e4
deviceId: 164c
subVendorId: 103c
subDeviceId: 7038
pciType: 1
pcidom:    0
pcibus:  5
pcidev:  0
pcifn:  0
-
class: NETWORK
bus: PCI
detached: 0
device: eth0
driver: bnx2
desc: "Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet"
network.hwaddr: 00:1B:78:97:E4:EC
vendorId: 14e4
deviceId: 164c
subVendorId: 103c
subDeviceId: 7038
pciType: 1
pcidom:    0
pcibus:  3
pcidev:  0
pcifn:  0

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03:02 250G硬盘装到小黑上了！ (1245 Bytes) » OracleDBA Blog---请享受无法回避的痛苦!

准备在7，8，9这三个不忙的月份，好好的奋发学习下ORACLE，作作试验。就买了个250G的硬盘，把原来的80G的硬盘从小黑上换下来了。

现在的感觉，很象暴发户，以前呀，看到很多好东西想放机器上，总是空间不足，每次都要去忍痛删除一些东西，现在终于不用了，我想放哪里放哪里，想放啥放啥，呵呵。真开心的来。

好好搞点资料看看，视频教程呀，不过不知道能不能下到OCM的视频教程。然后搞点啥列，哦，对了，搞个VMWARE的RAC环境，以前一套都搞不了，现在，俺搞两套，一套作主库，另外一套作DG的容灾环境。这样不就是想搞啥都可以了吗？

下一步该把2G的内存换到最少4G了，要不DG环境搭不起来。嗯，攒钱，买内存！

PS：最坏的是小占同学了，听说我用上了250G的硬盘，直接告诉我说 D:/JAPAN/AV 200G，唉，这孩子，从哪里学的呀。算算也不化算吗，去电子市场，RMB 5元的，500块可以买100张，500G了，我这才200G，多亏呀是吧。坚决不上那孩子的当。开始学习了，要相信知识改变命运，学习成就未来！

01:31 Oracle 10gR2 软件下载网址收藏 (4680 Bytes) » Oracle Life

©作者：eygle 发布在 eygle.com

记录一下ORACLE 10gR2的软件下载地址，备用。

下载OTN上的这些软件，你需要一个OTN免费帐号，不过如果通过迅雷进行下载，就不用登陆OTN了：
Oracle Database 10g Release 2 (10.2.0.1.0) Enterprise/Standard Edition for Microsoft Windows (32-bit)

http://download.oracle.com/otn/nt/oracle10g/10201/10201_database_win32.zip
http://download.oracle.com/otn/nt/oracle10g/10201/10201_client_win32.zip
http://download.oracle.com/otn/nt/oracle10g/10201/10201_clusterware_win32.zip
http://download.oracle.com/otn/nt/oracle10g/10201/10201_gateways_win32.zip

Oracle Database 10g Release 2 (10.2.0.1.0) Enterprise/Standard Edition for Microsoft Windows (x64)

http://download.oracle.com/otn/nt/oracle10g/10201/102010_win64_x64_database.zip
http://download.oracle.com/otn/nt/oracle10g/10201/102010_win64_x64_client.zip
http://download.oracle.com/otn/nt/oracle10g/10201/102010_win64_x64_clusterware.zip

Oracle Database 10g Release 2 (10.2.0.1.0) Enterprise/Standard Edition for Linux x86

http://download.oracle.com/otn/linux/oracle10g/10201/10201_database_linux32.zip
http://download.oracle.com/otn/linux/oracle10g/10201/10201_client_linux32.zip
http://download.oracle.com/otn/linux/oracle10g/10201/10201_gateways_linux32.zip

Oracle Database 10g Release 2 (10.2.0.1.0) Enterprise/Standard Edition for Linux x86-64

http://download.oracle.com/otn/linux/oracle10g/10201/10201_database_linux_x86_64.cpio.gz
http://download.oracle.com/otn/linux/oracle10g/10201/10201_client_linux_x86_64.cpio.gz
http://download.oracle.com/otn/linux/oracle10g/10201/10201_clusterware_linux_x86_64.cpio.gz
http://download.oracle.com/otn/linux/oracle10g/10201/10201_gateways_linux_x86_64.cpio.gz

Oracle Database 10g Release 2 (10.2.0.1.0) Enterprise/Standard Edition for AIX5L

http://download.oracle.com/otn/aix/oracle10g/10201/10gr2_aix5l64_database.cpio.gz
http://download.oracle.com/otn/aix/oracle10g/10201/10gr2_aix5l64_client.cpio.gz
http://download.oracle.com/otn/aix/oracle10g/10201/10gr2_aix5l64_cluster.cpio.gz
http://download.oracle.com/otn/aix/oracle10g/10201/10gr2_aix5l64_gateways.cpio.gz

Oracle Database 10g Release 2 (10.2.0.2) Enterprise/Standard Edition for Solaris Operating System (x86)

http://download.oracle.com/otn/solaris/oracle10g/10202/10202_database_solx86.zip
http://download.oracle.com/otn/solaris/oracle10g/10202/10202_client_solx86.zip
http://download.oracle.com/otn/solaris/oracle10g/10202/10202_clusterware_solx86.zip

Oracle Database 10g Release 2 (10.2.0.1.0) Enterprise/Standard Edition for Solaris Operating System (x86-64)

http://download.oracle.com/otn/solaris/oracle10g/10201/x8664/10201_database_solx86_64.zip
http://download.oracle.com/otn/solaris/oracle10g/10201/x8664/10201_client_solx86_64.zip
http://download.oracle.com/otn/solaris/oracle10g/10201/x8664/10201_clusterware_solx86_64.zip

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01:30 HACMP 认证学习系列，第 5 部分：后期安装工作和管理任务（3） (471 Bytes) » developerWorks 中国 : 技术文章 , 教程 AIX

本文介绍了在常规集群操作过程中应执行的后期安装工作和管理任务。维护一个集群配置并将更改应用到一个正在运行的集群需要严格的过程和更改管理；否则，集群可能无法维持平衡，并且在出现故障时可能无法按设计的方式进行响应（故障转移）。系统管理员和应用程序管理员必须密切协作，维护一个正常运行的集群，使之总能够提供预期的结果。

01:30 HACMP 认证学习系列，第 5 部分：后期安装工作和管理任务（2） (471 Bytes) » developerWorks 中国 : 技术文章 , 教程 AIX

本文介绍了在常规集群操作过程中应执行的后期安装工作和管理任务。维护一个集群配置并将更改应用到一个正在运行的集群需要严格的过程和更改管理；否则，集群可能无法维持平衡，并且在出现故障时可能无法按设计的方式进行响应（故障转移）。系统管理员和应用程序管理员必须密切协作，维护一个正常运行的集群，使之总能够提供预期的结果。

01:30 HACMP 认证学习系列，第 5 部分：后期安装工作和管理任务（1） (471 Bytes) » developerWorks 中国 : 技术文章 , 教程 AIX

本文介绍了在常规集群操作过程中应执行的后期安装工作和管理任务。维护一个集群配置并将更改应用到一个正在运行的集群需要严格的过程和更改管理；否则，集群可能无法维持平衡，并且在出现故障时可能无法按设计的方式进行响应（故障转移）。系统管理员和应用程序管理员必须密切协作，维护一个正常运行的集群，使之总能够提供预期的结果。

00:50 Paypal遭遇中国支付 (5425 Bytes) » Fenng's shared items in Google Reader

paypal是美国ebay公司推出的在线支付工具，在美国和英文国家使用率较高，不过今年对于paypal来说十分不爽，先是遇上自身平台bug损失数百万美金，接着收到澳大利亚网民集体抗议。同时，美国经济衰退的大形势给了paypal母公司ebay巨大压力，Sanford C. Bernstein分析师杰弗里·林德塞(Jeffrey Lindsay)指出，ebay未来被收购的可能性很大。

失误连连，paypal屡受用户职责

据博客网站TechCrunch报道，paypal的用户支付系统于5月16日出现一个Bug，导致所有用户无法向其他国家的用户付款。有用户抱怨称，这一Bug可能导致总额达数百万美元的损失。一名商家指出，paypal未能及时修复这一问题令人吃惊。而当该商家与paypal客服联系之后，paypal表示已经知道这一问题的存在，但是仍不能提供准确的修复Bug的时间。这名商家认为，paypal在提供稳定的支付系统方面并不值得信赖。

ebay在澳大利亚强制用户只能使用paypal进行支付，受到澳大利亚用户和同行的强烈不满，并引发当地的反垄断调查，澳大利亚当地的竞争及消费者委员会正在对此进行调查。澳大利亚银行团体称PayPal并不能如eBay所吹嘘的能避免欺诈。PayPal确实可以保持交易各方的银行及信用卡资料等机密不被泄露，它并没有像一般银行那样进行身份验证，不上商家担心买家会由于被剥夺选择权而流失。

中国支付走出国门，Paypal遭遇国际挑战

就在paypal在澳洲被指责的同时，中国的支付公司支付宝与澳大利亚在线支付公司Paymate达成合作协议。Paymate将成为支付宝的合作代理机构，中国上千万的消费者足不出户，即可在线选购由澳大利亚商户提供的各类商品。paypal在国际市场上再次遭遇老对手，自身的国际市场地位开始遭遇中国支付的挑战。

2007年8月，支付宝公司正式推出支持十二种海外货币的海外业务，正式走出国门。通过此项服务，当一笔网上海外交易发生时，支付宝将以买家的身份，帮助买家在境内合作银行用人民币购得外币，并结算给卖家，向海内买家和海外卖家提供一站式的资金结算解决方案，彻底解决跨境网上交易的资金流问题

paypal在美国的模式并没有受到中国网民的认可，而中国支付市场的老大支付宝恰恰是打造了一套被认可的信用机制，并且几乎成本行业的标准和标尺，支付宝以其开放性被广泛使用于整个电子商务领域，而不仅仅是淘宝和阿里系企业。支付宝通过合作方式向澳洲进军，标志着全球电子商务开始享用中国支付的信用机制，paypal开始遭遇中国支付宝的全球性挑战。

支付宝成于信用，赢在开放

支付宝的成功毫无疑问是因为带来了网民信赖的信用机制，通过其开放式的运营，实现了服务产业链的共赢局面。著名经济学家郎咸平说过，“现在的市场竞争不是一个产品的竞争，也不是一个企业的竞争，而是整个产业链的竞争。”所以，支付宝的开放性是产业链的需求，而我们中国支付走出国门也必将是一场中国信用和中国开放的世纪之旅，其意义绝对不仅仅在于电子商务，而是赢得外国人对中国人的尊敬。