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Linux Shell

23 Kvm Storage Performance and Cache Settings on Red Hat Enterprise Linux 62

Almost one year ago, I checked how different cache settings affected KVM storage subsystem performance. Results were very clear: to obtain good I/O speed, you had to use the write-back or none cache policies, avoiding the write-through one. However, as the write-back policy intrinsic comported some data-loss risk, the safer bullet was to not use any host-based cache (the “nocache” KVM option).

But what is the situation now? With the newly released RHEL 6.2 point release, I am going to check if something has changed. But let me first recap the whole KVM caching question.

国内到国际的各种ISP线路

写在开头

我近期正在研究国际ISP线路,偶然发现了这篇文章。作者非常用心地科普了国内外的ISP知识,内容极具学习价值。我想将其保存在博客中作为备份,在此由衷感谢各位作者的分享。

如何关闭Outlook添加账户时的简易模式

win10自带的mail App 经常提醒切换到新版的Outlook,但是这个版本只能添加10个邮箱账户,就想着直接使用Outlook 365 得了,结果在迁移账户时,有个腾讯企业邮箱始终无法添加,原因是Outlook默认使用简易的方式添加账户,自动将服务器地址识别成了 smtp.qq.com,而实际上的地址应该是 smtp.exmail.qq.com,简易模式的高级方式,同样只允许输入邮箱账户和密码,不允许自定义服务器地址,高级了个寂寞。

在 Openwrt 中,禁止某个设备访问外网/内网

最近刷了某个AP固件,自带了一些云管理功能,发现它会收集mac地址并上传到服务器以及通过访问一些网站来达到检测网络状态的目的,个人只想它安安静静的做个AP就好了,不需要这些乱七八糟的功能,所以就在openwrt主路由上通过防火墙规则的方式来禁止它访问外网。