varnish

Apache + Ubuntu + Varnish painless upgrades

Varnish is a reverse proxy
working with apache, with all traffic go thriugh Varnish cache first
if cache missed, Varnish will be the one to grab content from Apache
It is because Apache ignore file types
For example, deliver a jpg by Apache will load mod_php into RAM
the same applies to CSS and JS files
This will cause massive RAM footage
And Varnish cache help greatly helped these static files with less resources drain
and improve overall performance

My target is install Varnish with minimum downtime
Remember to backup the config files before continue

Apache + Ubuntu + Varnish 無痛升級

Varnish 是一個「反向」的代理 (reverse proxy)
用法是和你的 Apache 一起,所有的流量都先經過 Varnish 的緩存
緩存落空後才由 Varnish 向 Apache 拿資料
因為 Apache 的結構是沒有針對檔案類別的
例如 Apache 送出一張圖片一樣會將 mod_php 載入到 RAM 內
同例可用於 CSS, JS 等靜態的檔案
做成大量的 RAM 浪費
而Varnish 的緩存可大大幫助這類靜態檔案佔用的資源
從而提升整體的效能

這次我的目標是用最少的下線時間安裝和設置 Varnish
大家記得一定要先備份有關設定的檔案

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