mirror of
https://github.com/adambard/learnxinyminutes-docs.git
synced 2024-11-23 22:27:35 +03:00
398 lines
14 KiB
Markdown
398 lines
14 KiB
Markdown
---
|
||
category: tool
|
||
tool: zfs
|
||
contributors:
|
||
- ["sarlalian", "http://github.com/sarlalian"]
|
||
translators:
|
||
- ["Alan Cheng", "https://github.com/kedaio"]
|
||
filename: LearnZfs-cn.txt
|
||
lang: zh-cn
|
||
---
|
||
|
||
[ZFS](http://open-zfs.org/wiki/Main_Page)
|
||
是重新思考与储存相关技术的结果，它把传统的文件系统和卷管理器集成到一个工具当中.
|
||
ZFS不但有把它和传统存储系统分开来的特有术语，也有很多聚焦于可用性的功能。
|
||
|
||
|
||
## ZFS概念
|
||
|
||
### 虚拟设备（Virtual Devices，VDEV）
|
||
|
||
对于操作系统来说，VDEV和传统的RAID阵列卡所呈现的raid设备类似。VDEV有几种不同的类型，每种类型
|
||
都有自己的优势，包括冗余和速度。一般来说，VDEV的可靠性和安全性比阵列卡要好。因此使用ZFS时不
|
||
建议使用阵列卡。让ZFS直接管理磁盘。
|
||
|
||
VDEV的类型
|
||
* stripe (条带。单个磁盘，没有冗余)
|
||
* mirror (镜像。支持n-way镜像)
|
||
* raidz
|
||
* raidz1 (一个奇偶校验磁盘, 类似于RAID 5)
|
||
* raidz2 (两个奇偶校验磁盘, 类似于RAID 6)
|
||
* raidz3 (三个奇偶校验磁盘, 没有类似RAID等级)
|
||
* disk （磁盘）
|
||
* file (文件。不推荐在生产环境中使用，因为中间又多了一层不必要的文件系统)
|
||
|
||
数据会以条带方式存储于存储池中的所有VDEV上。因此一个存储池中的VDEV越多，IOPS就越高。
|
||
|
||
### storage pool （存储池）
|
||
|
||
ZFS 使用存储池来作为底层存储提供者（VDEV）的抽象。这样可以把用户可见的文件系统和底层的物理磁盘
|
||
布局分离开来。
|
||
|
||
### ZFS 数据集（Dataset）
|
||
|
||
ZFS 数据集类似于传统的文件系统（译者注：或者说是目录），但是提供了更多的功能。ZFS的很多优势也是
|
||
在这一层体现出来的。数据集支持 [Copy on Write](https://en.wikipedia.org/wiki/Copy-on-write)
|
||
快照, 配额, 压缩和重复消除（de-duplication）.
|
||
|
||
|
||
### 限制
|
||
|
||
一个目录最多可包含 2^48个文件, 每个文件最大可以是16 exabytes. 一个存储池最大可包含256 zettabytes 、
|
||
(2^78) 的空间, 可以条带化地分布于2^64 设备上. 单一主机最多可以创建2^64个存储池。这些限制可以说是相
|
||
当大。
|
||
|
||
|
||
## 命令
|
||
|
||
### 存储池
|
||
|
||
Actions: （存储池操作）
|
||
* List （列举）
|
||
* Status （查看状态）
|
||
* Destroy （删除）
|
||
* Get/Set properties （获取/设置属性）
|
||
|
||
List zpools （列举存储池（也叫zpool））
|
||
|
||
```bash
|
||
# 创建一个raidz类型的存储池(名称为bucket）
|
||
$ zpool create bucket raidz1 gpt/zfs0 gpt/zfs1 gpt/zfs2
|
||
|
||
# 列出所有存储池
|
||
$ zpool list
|
||
NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
|
||
zroot 141G 106G 35.2G - 43% 75% 1.00x ONLINE -
|
||
|
||
# 列出某一存储池的详细信息
|
||
$ zpool list -v zroot
|
||
NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
|
||
zroot 141G 106G 35.2G - 43% 75% 1.00x ONLINE -
|
||
gptid/c92a5ccf-a5bb-11e4-a77d-001b2172c655 141G 106G 35.2G - 43% 75%
|
||
```
|
||
|
||
Status of zpools （存储池状态）
|
||
|
||
```bash
|
||
# 获取全部zpool状态信息
|
||
$ zpool status
|
||
pool: zroot
|
||
state: ONLINE
|
||
scan: scrub repaired 0 in 2h51m with 0 errors on Thu Oct 1 07:08:31 2015
|
||
config:
|
||
|
||
NAME STATE READ WRITE CKSUM
|
||
zroot ONLINE 0 0 0
|
||
gptid/c92a5ccf-a5bb-11e4-a77d-001b2172c655 ONLINE 0 0 0
|
||
|
||
errors: No known data errors
|
||
|
||
# 用scrub来更正存储池错误信息
|
||
$ zpool scrub zroot
|
||
$ zpool status -v zroot
|
||
pool: zroot
|
||
state: ONLINE
|
||
scan: scrub in progress since Thu Oct 15 16:59:14 2015
|
||
39.1M scanned out of 106G at 1.45M/s, 20h47m to go
|
||
0 repaired, 0.04% done
|
||
config:
|
||
|
||
NAME STATE READ WRITE CKSUM
|
||
zroot ONLINE 0 0 0
|
||
gptid/c92a5ccf-a5bb-11e4-a77d-001b2172c655 ONLINE 0 0 0
|
||
|
||
errors: No known data errors
|
||
```
|
||
|
||
Properties of zpools （存储池属性）
|
||
|
||
```bash
|
||
|
||
# 获取某一存储池的全部属性。属性可能是系统提供，也可能是用户设置
|
||
$ zpool get all zroot
|
||
NAME PROPERTY VALUE SOURCE
|
||
zroot size 141G -
|
||
zroot capacity 75% -
|
||
zroot altroot - default
|
||
zroot health ONLINE -
|
||
...
|
||
|
||
# 设置存储池属性，下例这是设置comment(备注)属性
|
||
$ zpool set comment="Storage of mah stuff" zroot
|
||
$ zpool get comment
|
||
NAME PROPERTY VALUE SOURCE
|
||
tank comment - default
|
||
zroot comment Storage of mah stuff local
|
||
```
|
||
|
||
Remove zpool （删除存储池）
|
||
|
||
```bash
|
||
$ zpool destroy test
|
||
```
|
||
|
||
|
||
### Datasets （数据集）
|
||
|
||
Actions: （数据集相关操作）
|
||
* Create （创建）
|
||
* List （列举）
|
||
* Rename （重命名）
|
||
* Delete （删除）
|
||
* Get/Set properties （获取/设置属性）
|
||
|
||
Create datasets
|
||
|
||
```bash
|
||
# 创建数据集
|
||
$ zfs create tank/root/data
|
||
$ mount | grep data
|
||
tank/root/data on /data (zfs, local, nfsv4acls)
|
||
|
||
# 创建子数据集
|
||
$ zfs create tank/root/data/stuff
|
||
$ mount | grep data
|
||
tank/root/data on /data (zfs, local, nfsv4acls)
|
||
tank/root/data/stuff on /data/stuff (zfs, local, nfsv4acls)
|
||
|
||
|
||
# 创建卷
|
||
$ zfs create -V zroot/win_vm
|
||
$ zfs list zroot/win_vm
|
||
NAME USED AVAIL REFER MOUNTPOINT
|
||
tank/win_vm 4.13G 17.9G 64K -
|
||
```
|
||
|
||
List datasets （列举数据集）
|
||
|
||
```bash
|
||
# 列出所有数据集
|
||
$ zfs list
|
||
NAME USED AVAIL REFER MOUNTPOINT
|
||
zroot 106G 30.8G 144K none
|
||
zroot/ROOT 18.5G 30.8G 144K none
|
||
zroot/ROOT/10.1 8K 30.8G 9.63G /
|
||
zroot/ROOT/default 18.5G 30.8G 11.2G /
|
||
zroot/backup 5.23G 30.8G 144K none
|
||
zroot/home 288K 30.8G 144K none
|
||
...
|
||
|
||
# 列举某一数据集的信息
|
||
$ zfs list zroot/home
|
||
NAME USED AVAIL REFER MOUNTPOINT
|
||
zroot/home 288K 30.8G 144K none
|
||
|
||
# 列出快照
|
||
$ zfs list -t snapshot
|
||
zroot@daily-2015-10-15 0 - 144K -
|
||
zroot/ROOT@daily-2015-10-15 0 - 144K -
|
||
zroot/ROOT/default@daily-2015-10-15 0 - 24.2G -
|
||
zroot/tmp@daily-2015-10-15 124K - 708M -
|
||
zroot/usr@daily-2015-10-15 0 - 144K -
|
||
zroot/home@daily-2015-10-15 0 - 11.9G -
|
||
zroot/var@daily-2015-10-15 704K - 1.42G -
|
||
zroot/var/log@daily-2015-10-15 192K - 828K -
|
||
zroot/var/tmp@daily-2015-10-15 0 - 152K -
|
||
```
|
||
|
||
Rename datasets （重命名数据集）
|
||
|
||
```bash
|
||
$ zfs rename tank/root/home tank/root/old_home
|
||
$ zfs rename tank/root/new_home tank/root/home
|
||
```
|
||
|
||
Delete dataset （删除数据集）
|
||
|
||
```bash
|
||
# 数据集如果有快照则无法删除
|
||
zfs destroy tank/root/home
|
||
```
|
||
|
||
Get / set properties of a dataset （获取/设置数据集属性）
|
||
|
||
```bash
|
||
# 获取数据集全部属性
|
||
$ zfs get all zroot/usr/home │157 # Create Volume
|
||
NAME PROPERTY VALUE SOURCE │158 $ zfs create -V zroot/win_vm
|
||
zroot/home type filesystem - │159 $ zfs list zroot/win_vm
|
||
zroot/home creation Mon Oct 20 14:44 2014 - │160 NAME USED AVAIL REFER MOUNTPOINT
|
||
zroot/home used 11.9G - │161 tank/win_vm 4.13G 17.9G 64K -
|
||
zroot/home available 94.1G - │162 ```
|
||
zroot/home referenced 11.9G - │163
|
||
zroot/home mounted yes -
|
||
...
|
||
|
||
# 获取数据集属性
|
||
$ zfs get compression zroot/usr/home
|
||
NAME PROPERTY VALUE SOURCE
|
||
zroot/home compression off default
|
||
|
||
# 设置数据集属性（下例为设置压缩属性compression）
|
||
$ zfs set compression=gzip-9 mypool/lamb
|
||
|
||
# 列举所有数据集的名称、配额和预留属性
|
||
$ zfs list -o name,quota,reservation
|
||
NAME QUOTA RESERV
|
||
zroot none none
|
||
zroot/ROOT none none
|
||
zroot/ROOT/default none none
|
||
zroot/tmp none none
|
||
zroot/usr none none
|
||
zroot/home none none
|
||
zroot/var none none
|
||
...
|
||
```
|
||
|
||
|
||
### Snapshots （快照）
|
||
|
||
快照是ZFS 的一个非常重要的功能
|
||
|
||
* 快照占用的空间等于它和原始数据的差异量
|
||
* 创建时间以秒计
|
||
* 恢复时间和写入速度相同
|
||
* 易于自动化
|
||
|
||
Actions: （快照相关操作）
|
||
* Create （创建）
|
||
* Delete （删除）
|
||
* Rename （重命名）
|
||
* Access snapshots （访问）
|
||
* Send / Receive （发送/接收）
|
||
* Clone （克隆。译者注：关于clone和快照的区别可参看[这里](http://docs.oracle.com/cd/E19253-01/819-5461/gbcxz/index.html)）
|
||
|
||
|
||
Create snapshots （创建快照）
|
||
|
||
```bash
|
||
# 为单一数据集创建快照
|
||
zfs snapshot tank/home/sarlalian@now
|
||
|
||
# 为数据集及其子集创建快照
|
||
$ zfs snapshot -r tank/home@now
|
||
$ zfs list -t snapshot
|
||
NAME USED AVAIL REFER MOUNTPOINT
|
||
tank/home@now 0 - 26K -
|
||
tank/home/sarlalian@now 0 - 259M -
|
||
tank/home/alice@now 0 - 156M -
|
||
tank/home/bob@now 0 - 156M -
|
||
...
|
||
|
||
Destroy snapshots （删除快照）
|
||
|
||
```bash
|
||
# 如何删除快照
|
||
$ zfs destroy tank/home/sarlalian@now
|
||
|
||
# 删除某一数据集及其子集的快照
|
||
$ zfs destroy -r tank/home/sarlalian@now
|
||
|
||
```
|
||
|
||
Renaming Snapshots （重命名）
|
||
|
||
```bash
|
||
# 重命名快照
|
||
$ zfs rename tank/home/sarlalian@now tank/home/sarlalian@today
|
||
$ zfs rename tank/home/sarlalian@now today
|
||
|
||
# zfs rename -r tank/home@now @yesterday
|
||
```
|
||
|
||
Accessing snapshots （访问快照）
|
||
|
||
```bash
|
||
# cd进入一个快照目录
|
||
$ cd /home/.zfs/snapshot/
|
||
```
|
||
|
||
Sending and Receiving
|
||
|
||
```bash
|
||
# 备份快照到一个文件
|
||
$ zfs send tank/home/sarlalian@now | gzip > backup_file.gz
|
||
|
||
# 发送快照到另一个数据集
|
||
$ zfs send tank/home/sarlalian@now | zfs recv backups/home/sarlalian
|
||
|
||
# 发送快照到一个远程主机
|
||
$ zfs send tank/home/sarlalian@now | ssh root@backup_server 'zfs recv tank/home/sarlalian'
|
||
|
||
# 发送完整数据集及其快照到一个新主机
|
||
$ zfs send -v -R tank/home@now | ssh root@backup_server 'zfs recv tank/home'
|
||
```
|
||
|
||
Cloneing Snapshots （克隆快照）
|
||
|
||
```bash
|
||
# 克隆一个快照
|
||
$ zfs clone tank/home/sarlalian@now tank/home/sarlalian_new
|
||
|
||
# 提升克隆，让它不再依赖原始快照
|
||
$ zfs promote tank/home/sarlalian_new
|
||
```
|
||
|
||
### 汇总
|
||
|
||
下面这个脚本使用了FreeBSD, jails和ZFS，来自动在一个mysql群集的热备主机上为一个mysq staging数据库
|
||
创建一份纯净的拷贝。
|
||
|
||
```bash
|
||
#!/bin/sh
|
||
|
||
echo "==== Stopping the staging database server ===="
|
||
jail -r staging
|
||
|
||
echo "==== Cleaning up existing staging server and snapshot ===="
|
||
zfs destroy -r zroot/jails/staging
|
||
zfs destroy zroot/jails/slave@staging
|
||
|
||
echo "==== Quiescing the slave database ===="
|
||
echo "FLUSH TABLES WITH READ LOCK;" | /usr/local/bin/mysql -u root -pmyrootpassword -h slave
|
||
|
||
echo "==== Snapshotting the slave db filesystem as zroot/jails/slave@staging ===="
|
||
zfs snapshot zroot/jails/slave@staging
|
||
|
||
echo "==== Starting the slave database server ===="
|
||
jail -c slave
|
||
|
||
echo "==== Cloning the slave snapshot to the staging server ===="
|
||
zfs clone zroot/jails/slave@staging zroot/jails/staging
|
||
|
||
echo "==== Installing the staging mysql config ===="
|
||
mv /jails/staging/usr/local/etc/my.cnf /jails/staging/usr/local/etc/my.cnf.slave
|
||
cp /jails/staging/usr/local/etc/my.cnf.staging /jails/staging/usr/local/etc/my.cnf
|
||
|
||
echo "==== Setting up the staging rc.conf file ===="
|
||
mv /jails/staging/etc/rc.conf.local /jails/staging/etc/rc.conf.slave
|
||
mv /jails/staging/etc/rc.conf.staging /jails/staging/etc/rc.conf.local
|
||
|
||
echo "==== Starting the staging db server ===="
|
||
jail -c staging
|
||
|
||
echo "==== Makes the staging database not pull from the master ===="
|
||
echo "STOP SLAVE;" | /usr/local/bin/mysql -u root -pmyrootpassword -h staging
|
||
echo "RESET SLAVE;" | /usr/local/bin/mysql -u root -pmyrootpassword -h staging
|
||
```
|
||
|
||
|
||
### 延伸阅读
|
||
|
||
* [BSDNow's Crash Course on ZFS](http://www.bsdnow.tv/tutorials/zfs)
|
||
* [FreeBSD Handbook on ZFS](https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/zfs.html)
|
||
* [BSDNow's Crash Course on ZFS](http://www.bsdnow.tv/tutorials/zfs)
|
||
* [Oracle's Tuning Guide](http://www.oracle.com/technetwork/articles/servers-storage-admin/sto-recommended-zfs-settings-1951715.html)
|
||
* [OpenZFS Tuning Guide](http://open-zfs.org/wiki/Performance_tuning)
|
||
* [FreeBSD ZFS Tuning Guide](https://wiki.freebsd.org/ZFSTuningGuide)
|