记录1-更换mac pro内存，硬盘及恢复系统

我的mac pro是2012年初买的，4G/500G HDD在服役了六年多后速度堪比老牛，以前装的虚拟机压根不敢打开。这几天把内存更换为8G，硬盘升级为samsung的1T SSD，感觉像起死回生一样。预留此文，准备把更换过程记录一下。

1. 更换内存，Amazon上按照好评度和性价比买来匹配2011 late mac pro的内存双条装，4G*2

Crucial 8GB Kit (4GBx2) DDR3/DDR3L 1333 MT/s (PC3-10600) SODIMM 204-Pin Memory For Mac - CT2K4G3S1339M。

此处需要注意的是，打开后盖后的螺丝最好按照当初位置摆好，硬件更换完毕后再原样装回去。虽然有些螺丝长得差不多，但一旦换个位置装却往往不能完全装进去，突出一块：（

2. 选择一个足够大的移动硬盘，用time machine备份当前macOS，我备份了好几个小时，400G+

3. 制作macos的U盘启动盘，直接去apple官网查guide如下：

Download macOS from the App Store

Download macOS from the App Store. To download, use a Mac that is compatible with the version of macOS you're downloading.
If you're downloading macOS High Sierra, use a Mac with High Sierra, Sierra 10.12.5 or later, or El Capitan 10.11.6. Enterprise administrators: Please download from Apple, not a locally hosted software-update server.
When the macOS installer opens, quit it without continuing installation.
Find the installer in your Applications folder as a single ”Install” file, such as Install macOS High Sierra.

Use the 'createinstallmedia' command in Terminal

After downloading the installer, connect your Mac to the USB flash drive or other volume that will be used as the bootable installer. Make sure that it has at least 12GB of available storage.
Open Terminal, which is in the Utilities folder of your Applications folder.
Type or paste one of the following commands in Terminal. These assume that the installer is still in your Applications folder, and the name of your volume is MyVolume. If it's named differently, replace MyVolume accordingly.

High Sierra:
```
sudo /Applications/Install macOS High Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install macOS High Sierra.app
```
Press Return after typing the command.
When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
When prompted, type Y to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the bootable installer is created.
Quit Terminal when done.

有个帖子写的很具体，见https://www.jianshu.com/p/2ff576583361，只不过我当前系统是high sierra，而链接中的是EI Capitan。回头再把此帖子转过来。

4. Amazon上买来专用螺丝刀，拆除旧硬盘，安装新硬盘。

5. 用U盘启动，此处引用官方guide：

Use the bootable installer

Connect the volume containing the bootable installer to a compatible Mac，由于我已经备份了当前系统，就把备份用的移动硬盘也连接在电脑上
Use Startup Disk preferences or Startup Manager to select that volume as the startup disk. Learn about selecting a startup disk, including what to do if your Mac doesn't start up from it.
Your Mac then starts up directly to the macOS installer. Follow the onscreen instructions to install macOS
另外，先用“磁盘工具”将新硬盘格式化
另外，我在安装时选择了“从time machine备份进行恢复”，并选择之前备份用的移动硬盘，由于备份太大，安装经历了好几个小时。这里奇怪的是，我第一次安装失败了，不知是何原因，后来我同样操作了一遍又安装成功了。在第一遍安装还差半小时完成时，我在娃的召唤下去睡觉了，半夜爬起来发现居然死机了。于是又重新U盘boot起来，同样的步骤选择一遍“从time machine备份进行恢复”，第二天早晨起床时又发现安装成功了。

安装完毕后，登录进电脑，系统还是那个系统，但是速度嗖嗖嗖嗖嗖嗖：）