“华为四核honor”与小米2同一天登陆

    看到一条新闻,华为推出了"honor四核版"手机,售价也只有1888元。海思 K3V2四核1.4GHz处理器、4.5英寸1280×720分辨率 IPS屏幕,拥有2G RAM,摄像头达到800万像素,电池容量2230mAh。在加上今天是期待已久的小米2的网络发售时间,中午的时候在我努力的" 刷新"页面、"不断F5"时,面对半瘫不瘫的页面,nothing you can do but wait….终于,不到3分钟,终于有了反馈,售 罄、抢购完毕,88,11月再来,很无奈,还真是成了之前提过的"期货小米2"。曾想华为下午推出了这个利器,挑在这个时间点,不知华为终端是有意,还是 巧合,但看配置,小米2其实没太多亮点了,后者逐渐在赶上。

    其实,我一直有个观点:粘着用户的应该是易用的ROM(miui),而不是硬件配置。当下,手机的硬件配置已经不是瓶颈了,某种程度来讲,已经出现“配置 过剩”了,而小米做得不错的地方是在混乱的android市场上,一直在不断优化自己的rom,将其易用性不断提升,一直有不少的粉丝,用心可见。记得几 个月前,给父母买了小米,60左右的老人在两天内基本把功能摸熟了,其实这个就是最好的易用性体现,手机是否好用,让老年人或者没有“背景”的人用就可以 了,产品好坏很容易分辨出来。就当某个周五,老爹在应用小米例行的更新之后,惊奇的发现之前手机上已经硕大的字体,变得更大了,之前偏小的二级菜单字体也 变大了,老爹如获至宝,多年未解决的问题,在智能手机时代搞定了,我也松了一口气。要知道为了给老爹换个称心如意的手机,在市面上,我跑了很久,一直在山 寨手机里面找来找去的我,也终于卸下重担,仅仅是为了满足老人“字大”、“手写”的两个简单的需求。

   也许,只有老罗那样非常追求完美的家伙能做出超过miui的rom了,于是,非常期待一个月后老罗的ROM。

    华为应当完善自己的rom,在易用性上投入本来具备优势的研发力量,打造好自己的rom,加上华为在运营商那里耕耘这么多年,没有理由做得比miui差 的。当然,在变化迅速的互联网行业,华为欠缺的是“迅速”,如何让“大象跳舞”?面对快速变化的而用户需求,如何快速满足,打造好自己的产品?

    四 核,小米2会慢慢的面对很多四核的竞争对手,例如后面会问世的LG nexus 4:高通骁龙S4四核1.5GHz处理器,搭配的内存高达 2GB base on android 4.2,价格1900人民币,是的,没错,只有1900元,想必小米2背后是阵阵凉气。"期货小米2"随着时间 的推移,不久其性价比就不会再那么优势明显了,强敌在后,小心了,2012的第四季度,好戏上演,精彩连连。


–EOF–

 

 

how to set hangcheck for linux

客户询问在10g rac实施的时候,hangcheck模块的参数设置,我转了篇文档给他,以供参考。

support.oracle.com上有篇文档写得很清楚了,可以参考:

 

In this Document

  Purpose
  Scope
  Details
  References

 

Applies to:

Oracle Server – Enterprise Edition – Version 9.2.0.8 to 11.1.0.7 [Release 9.2 to 11.1]
Linux x86
Linux x86-64

Purpose

Hangcheck_timer module is required to run a supported configuration in Oracle Real Application Clusters environments on Linux, with Oracle releases 9i, 10g, or 11gR1 RAC.  This note identifies and outlines the requirements needed to configure hangcheck-timer in an Oracle Enterprise Linux, Red Hat Linux, or SUSE Linux environment.
 

Note : Hangheck timer is not required starting with Oracle Clusterware 11gR2

//oracle clusterware 11gr2之后,hangcheck模块不在被需要了。

Scope

This article is provided for product management, system architects, and system administrators involved in deploying and configuring Oracle RAC 9i, 10g, or 11gR1 in a Linux environment. This document will also be useful to field engineers and consulting organizations to facilitate installations and configuration requirements of Oracle in a Linux RAC environment.

Details

Starting in release 9.2.0.2 and later, Oracle RAC environments required using a new I/O fencing model, named the hangcheck-timer module. This module was implemented to replace the Watchdog module, which provided similar fencing functionality. Hangcheck-timer was subsequently delivered as part of the standard kernel distribution for Linux kernel releases 2.4 and above. 

Hangcheck-timer should be loaded at boot time, and monitors the Linux kernel for long operating system hangs that could affect the reliability of a RAC node.  It runs in kernel mode and uses the Time Stamp Counter (TSC) to catch scheduling delays or node hangs.  This is done by setting a timer, then checking when the timer fires as to whether it was delayed by more than the allowed margin of error.  If the duration exceeds the allowed time of (hangcheck_tick + hangcheck_margin seconds), the machine is restarted.  Hangcheck-timer will not cause reboots to occur due to CPU starvation.

 Hangcheck-timer requires three configuration parameters:

  • hangcheck_tick – defines how often, in seconds, the hangcheck-timer checks the node for hangs. The default value is 60 seconds.
  • hangcheck_margin – defines how much margin is allowed, in seconds, between expected scheduling and real scheduling time. The default value is 180 seconds.
  • hangcheck_reboot – determines if the hangcheck-timer restarts the node if the kernel fails to respond within the sum of the hangcheck_tick and hangcheck_margin parameter values. If the value of hangcheck_reboot is equal to or greater than 1, then the hangcheck-timer module restarts the system. If the hangcheck_reboot parameter is set to zero, then the hangcheck-timer module will not reboot the node, even if a hang is detected.   The default value varies by kernel version.  In the 2.4 kernel, the default is 1.  In 2.6 kernels, the default is 0.
All hangcheck-timer default values should be explicitly overridden when loading the kernel module, based on the Oracle release as follows: 
  • 9i: Assuming the default setting of "oracm misscount" is set to 220 seconds
    hangcheck_tick=30 hangcheck_margin=180 hangcheck_reboot=1
  • 10g/11gR1: Assuming the default setting of "CSS misscount" is set to either 30 or 60 seconds:
    hangcheck_tick=1 hangcheck_margin=10 hangcheck_reboot=1

You must always ensure that the Cluster misscount setting is greater than the sum of the setting for hangcheck_tick + hangcheck_margin.

@  Unpublished information for Oracle Support Internal Use: 

When running Oracle Clusterware on Linux, hangcheck-timer should always be configured on each RAC cluster node, as the functionality of this module is required to provide I/O Fencing to ensure no stray writes will occur from an evicted node in a RAC cluster.  To verify if the hangcheck-timer module is running on a node execute as the root or oracle user:
 

# /sbin/lsmod | grep hangcheck

 

hangcheck-timer         2672   0


If the hangcheck-timer module is loaded (running) you will see output similar to above. When hangcheck-timer is not loaded no output is generated, and the command prompt is returned to the user.

In an Oracle Enterprise Linux, Red Hat 4/5, or SUSE 9/10 environment the hangcheck-timer module is loaded using the modprobe command:
 

# modprobe hangcheck-timer  hangcheck_tick=1 hangcheck_margin=10 hangcheck_reboot=1


In order to ensure the module is loaded at boot time, you should also place the same command in the appropriate local command execution directory (e.g. /etc/rc.d/rc.local, or /etc/init.d/boot.local).  In earlier releases, hangcheck-timer was loaded using insmod in place of modprobe. Consult your release specific documentation to determine which initialization method is required.

Hangcheck-timer will provide message logging to the system messages log when a failure is detected, and a node restart is initiated by the module:

  • When Hangcheck-timer reboots it may leave "Hangcheck: hangcheck is restarting the machine" message in /var/log/messages
  • If you see the following message in /var/log/messages:  "Hangcheck: hangcheck value past margin!" this means a reboot was required but was not performed, because hangcheck_reboot was not set to 1.  If this message is seen, you must reload the hangcheck module as described earlier in this note, with the hangcheck_reboot value set to 1.


Known Issues

  • Bug:6125546 which can prevent hangcheck-timer from rebooting in RHEL4 (fixed in 2.6.9.56 or RHEL4.6)

 

 

Database – RAC/Scalability Community
To discuss this topic further with Oracle experts and industry peers, we encourage you to review, join or start a discussion in the My Oracle Support Database – RAC/Scalability Community

References

BUG:6125546 – FASTER FENCING: EXECUTE SYSREQ B IMMEDIATELY
NOTE:232355.1 – Hangcheck Timer FAQ
@NOTE:259487.1 – Hangcheck-Timer Module Details
NOTE:559365.1 – Using Diagwait as a diagnostic to get more information for diagnosing Oracle Clusterware Node evictions
NOTE:567730.1 – Changes in Oracle Clusterware on Linux with the 10.2.0.4 Patchset

还有一篇 "best practice on oracle10gRac on linux"可以用作实施参考。

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