Linux系统配额与RAID

本篇内容：

一、Linux下的系统配额

二、Linux下RAID

一、系统磁盘配额

设置和检查文件系统上的磁盘配额，预防用户使用超出允许量的空间，还要预防整个文件系统被意外填满。

综述
在内核中执行
以文件系统为单位启用
对不同组或者用户的策略不同
根据块或者节点进行限制
软限制（soft limit）：软限制： 警告限制，可以被突破

硬限制（hard limit）：最大可用限制，不可突破；

配额大小：以K为单位，以文件个数为单位

初始化
分区挂载选项：usrquota、grpquota
初始化数据库：quotacheck

执行
开启或者取消配额：quotaon、quotaoff
直接编辑配额：edquota username
在shell中直接编辑：
setquota usename 4096 5120 40 50 /foo
定义原始标准用户
edquota -p user1 user2

报告
用户调查：quota
配额概述：repquota
其它工具：warnquota

创建一个分区并格式化，然后挂载至/home目录下，对此目录实现磁盘配额

1、创建一个10G的分区并且格式化为ext4系统

[root@localhost ~]# fdisk /dev/sdb[root@localhost ~]# lsblk  /dev/sdbNAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINTsdb      8:16   0  90G  0 disk └─sdb1   8:17   0  10G  0 part [root@localhost ~]# mkfs.ext4 /dev/sdb1

2、将/home目录下的文件移动到其他目录，然后将/dev/sdb1挂载至home目录下，再将数据复制回来。

[root@localhost ~]# mv /home/* /testdir/ [root@localhost ~]# ls /home/[root@localhost ~]# [root@localhost ~]# mount /dev/sdb1 /home/    //将/dev/sdb1挂载至/home目录下[root@localhost ~]# ls /home/lost+found[root@localhost ~]# mv /testdir/* /home/    //将/home下原来的数据移动回来[root@localhost ~]# ls /home/lost+found  xiaoshui

3、写入/etc/fstab，并且将挂载选项设为usrquota，grpquota，因为刚刚没有写挂载选项，需要卸载后重新挂载。

[root@localhost ~]# vi /etc/fstab ## /etc/fstab# Created by anaconda on Mon Jul 25 09:34:22 2016## Accessible filesystems, by reference, are maintained under '/dev/disk'# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info#/dev/mapper/vg0-root    /                       ext4    defaults        1 1UUID=7bbc50de-dfee-4e22-8cb6-04d8520b6422 /boot                   ext4    defaults        1 2/dev/mapper/vg0-usr     /usr                    ext4    defaults        1 2/dev/mapper/vg0-var     /var                    ext4    defaults        1 2/dev/mapper/vg0-swap    swap                    swap    defaults        0 0tmpfs                   /dev/shm                tmpfs   defaults        0 0devpts                  /dev/pts                devpts  gid=5,mode=620  0 0sysfs                   /sys                    sysfs   defaults        0 0proc                    /proc                   proc    defaults        1 0/dev/sdb1               /home                   ext4    usrquota,grpquota 0 0    [root@localhost ~]# umount /home/[root@localhost ~]# mount -a

4、创建配额数据库

[root@localhost ~]# quotacheck -cug /home

5、启用数据库

[root@localhost ~]# quotaon -p /home    //查看是否启用数据库group quota on /home (/dev/sdb1) is off    user quota on /home (/dev/sdb1) is off[root@localhost ~]# quotaon  /home        //启用数据库

6、配置配额项

[root@localhost ~]# edquota xiaoshui    //soft为软限制，hard为硬限制Disk quotas for user xiaoshui (uid 500):  Filesystem                   blocks       soft       hard     inodes     soft     hard  /dev/sdb1                        32       300000     500000          8        0        0

7、切换到xiaoshui用户，来测试是否上述设置是否生效

[root@localhost ~]# su - xiaoshui        //切换用户只xiaoshui[xiaoshui@localhost ~]$ pwd/home/xiaoshui[xiaoshui@localhost ~]$ dd if=/dev/zero of=file1 bs=1M count=290    //先新建一个290MB的文件290+0 records in290+0 records out304087040 bytes (304 MB) copied, 1.08561 s, 280 MB/s    //创建成功，并没有报错[xiaoshui@localhost ~]$ dd if=/dev/zero of=file1 bs=1M count=300    //覆盖file1，创建一个300MB的文件sdb1: warning, user block quota exceeded.    //出现警告!300+0 records in300+0 records out314572800 bytes (315 MB) copied, 0.951662 s, 331 MB/s[xiaoshui@localhost ~]$ ll -h            查看文件，发现依然创建成功total 300M-rw-rw-r-- 1 xiaoshui xiaoshui 300M Aug 26 08:16 file1[xiaoshui@localhost ~]$ dd if=/dev/zero of=file1 bs=1M count=500    //继续覆盖file1，创建一个500MB的文件sdb1: warning, user block quota exceeded.sdb1: write failed, user block limit reached.    //出现警告，提示用户的block到了限制dd: writing `file1': Disk quota exceeded489+0 records in488+0 records out511967232 bytes (512 MB) copied, 2.344 s, 218 MB/s[xiaoshui@localhost ~]$ ll -h            //查看文件，发现并没有500MB的文件，系统自动dd过程停止了total 489M-rw-rw-r-- 1 xiaoshui xiaoshui 489M Aug 26 08:19 file1

8、报告配额状态

[root@localhost ~]# quota xiaoshui    //blocks显示了用户现在的文件block数，已经超过了limitDisk quotas for user xiaoshui (uid 500):      Filesystem  blocks   quota   limit   grace   files   quota   limit   grace      /dev/sdb1  500004* 300000  500000   6days      10       0       0

RAID

一、什么是RAID

RAID:Redundant Arrays of Inexpensive（Independent）Disks，多个磁盘合成一个"阵列"来提供更好的性能、冗余，或者两者都提供

优点：

提高IO能力：
磁盘并行读写
提高耐用性；
磁盘冗余来实现

二、RAID级别

RAID-0：条带卷，strip

读、写性能提升；
可用空间：N*min(S1,S2,...)
无容错能力
最少磁盘数：2, 2

RAID-1: 镜像卷，mirror

读性能提升、写性能略有下降；
可用空间：1*min(S1,S2,...)
有冗余能力
最少磁盘数：2, 2N

RAID-2
..
RAID-5

读、写性能提升
可用空间：(N-1)*min(S1,S2,...)
有容错能力：有校验位，允许最多1块磁盘损坏
最少磁盘数：3, 3+

RAID-6

读、写性能提升
可用空间：(N-2)*min(S1,S2,...)
有容错能力：允许最多2块磁盘损坏
最少磁盘数：4, 4+

RAID-10

读、写性能提升
可用空间：N*min(S1,S2,...)/2
有容错能力：每组镜像最多只能坏一块
最少磁盘数：4, 4+

RAID-01

先RAID0,在RAID1

软件实现RAID 5

1、准备磁盘分区

[root@localhost ~]# lsblk NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTsda      8:0    0   80G  0 disk ├─sda1   8:1    0  488M  0 part /boot├─sda2   8:2    0   40G  0 part /├─sda3   8:3    0   20G  0 part /usr├─sda4   8:4    0  512B  0 part ├─sda5   8:5    0    2G  0 part [SWAP]└─sda6   8:6    0    1M  0 part sdb      8:16   0   80G  0 disk └─sdb1   8:17   0    1G  0 part sdc      8:32   0   20G  0 disk sdd      8:48   0   20G  0 disk ├─sdd1   8:49   0  100M  0 part ├─sdd2   8:50   0  100M  0 part ├─sdd3   8:51   0  100M  0 part ├─sdd4   8:52   0    1K  0 part └─sdd5   8:53   0   99M  0 part sde      8:64   0   20G  0 disk └─sde1   8:65   0  100M  0 part sdf      8:80   0   20G  0 disk sr0     11:0    1  7.2G  0 rom

准备四块磁盘分区，分区类型设为RAID类型(fd),我这里为/dev/sdd{1,2,3}，/dev/sde1

2、创建RAID 5

[root@localhost ~]# mdadm -C /dev/md0 -a yes -l 5 -n 3 -x1 /dev/sd{d{1,2,3},e1}mdadm: /dev/sdd1 appears to be part of a raid array:       level=raid5 devices=4 ctime=Mon Aug 29 19:43:21 2016mdadm: /dev/sdd2 appears to be part of a raid array:       level=raid0 devices=0 ctime=Thu Jan  1 08:00:00 1970mdadm: partition table exists on /dev/sdd2 but will be lost or       meaningless after creating arrayContinue creating array? yes     mdadm: Defaulting to version 1.2 metadatamdadm: array /dev/md0 started.[root@localhost ~]# mdadm  -D /dev/md0 /dev/md0:        Version : 1.2  Creation Time : Thu Sep  1 14:39:53 2016     Raid Level : raid5     Array Size : 202752 (198.03 MiB 207.62 MB)  Used Dev Size : 101376 (99.02 MiB 103.81 MB)   Raid Devices : 3  Total Devices : 4    Persistence : Superblock is persistent    Update Time : Thu Sep  1 14:39:54 2016          State : clean  Active Devices : 3Working Devices : 4 Failed Devices : 0  Spare Devices : 1         Layout : left-symmetric     Chunk Size : 512K           Name : localhost.localdomain:0  (local to host localhost.localdomain)           UUID : f4eaf910:514ae7ab:6dd6d28f:b6cfcc10         Events : 18    Number   Major   Minor   RaidDevice State       0       8       49        0      active sync   /dev/sdd1       1       8       50        1      active sync   /dev/sdd2       4       8       51        2      active sync   /dev/sdd3       3       8       65        -      spare   /dev/sde1[root@localhost ~]#

3、格式化文件系统

[root@localhost ~]# mkfs.ext4 /dev/md0 mke2fs 1.42.9 (28-Dec-2013)Filesystem label=OS type: LinuxBlock size=1024 (log=0)Fragment size=1024 (log=0)Stride=512 blocks, Stripe width=1024 blocks50800 inodes, 202752 blocks10137 blocks (5.00%) reserved for the super userFirst data block=1Maximum filesystem blocks=3381657625 block groups8192 blocks per group, 8192 fragments per group2032 inodes per groupSuperblock backups stored on blocks:     8193, 24577, 40961, 57345, 73729Allocating group tables: done                            Writing inode tables: done                            Creating journal (4096 blocks): doneWriting superblocks and filesystem accounting information: done

4、生成配置文件并启动RAID 5然后挂载

[root@localhost ~]# mdadm -Ds /dev/md0 > /etc/mdadm.conf[root@localhost ~]# mdadm -A /dev/md0 mdadm: /dev/md0 has been started with 3 drives and 1 spare.[root@localhost ~]# mount /dev/md0 /testdir/

5、测试

[root@localhost ~]# cd /testdir/[root@localhost testdir]# lslost+found[root@localhost testdir]# cp /etc/* .    //向挂载目录拷贝文件[root@localhost testdir]# mdadm -D /dev/md0     //查看RAID运行状态/dev/md0:        Version : 1.2  Creation Time : Thu Sep  1 14:39:53 2016     Raid Level : raid5     Array Size : 202752 (198.03 MiB 207.62 MB)  Used Dev Size : 101376 (99.02 MiB 103.81 MB)   Raid Devices : 3  Total Devices : 4    Persistence : Superblock is persistent    Update Time : Thu Sep  1 14:47:58 2016          State : clean  Active Devices : 3Working Devices : 4 Failed Devices : 0  Spare Devices : 1         Layout : left-symmetric     Chunk Size : 512K           Name : localhost.localdomain:0  (local to host localhost.localdomain)           UUID : f4eaf910:514ae7ab:6dd6d28f:b6cfcc10         Events : 18    Number   Major   Minor   RaidDevice State            //三个分区正常运行       0       8       49        0      active sync   /dev/sdd1       1       8       50        1      active sync   /dev/sdd2       4       8       51        2      active sync   /dev/sdd3       3       8       65        -      spare   /dev/sde1[root@localhost testdir]# mdadm /dev/md0 -f /dev/sdd1    //模拟/dev/sdd1损坏mdadm: set /dev/sdd1 faulty in /dev/md0[root@localhost testdir]# mdadm -D /dev/md0     //再次查看磁盘状态/dev/md0:        Version : 1.2  Creation Time : Thu Sep  1 14:39:53 2016     Raid Level : raid5     Array Size : 202752 (198.03 MiB 207.62 MB)  Used Dev Size : 101376 (99.02 MiB 103.81 MB)   Raid Devices : 3  Total Devices : 4    Persistence : Superblock is persistent    Update Time : Thu Sep  1 14:51:01 2016          State : clean  Active Devices : 3Working Devices : 3 Failed Devices : 1  Spare Devices : 0         Layout : left-symmetric     Chunk Size : 512K           Name : localhost.localdomain:0  (local to host localhost.localdomain)           UUID : f4eaf910:514ae7ab:6dd6d28f:b6cfcc10         Events : 37    Number   Major   Minor   RaidDevice State       3       8       65        0      active sync   /dev/sde1       1       8       50        1      active sync   /dev/sdd2       4       8       51        2      active sync   /dev/sdd3       0       8       49        -      faulty   /dev/sdd1    ///dev/sdd1已经标记为损坏，并且之前的/dev/sde1自动补上去了[root@localhost testdir]# cat fstab //依然正常查看文件## /etc/fstab# Created by anaconda on Mon Jul 25 12:06:44 2016## Accessible filesystems, by reference, are maintained under '/dev/disk'# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info#UUID=136f7cbb-d8f6-439b-aa73-3958bd33b05f /                       xfs     defaults        0 0UUID=bf3d4b2f-4629-4fd7-8d70-a21302111564 /boot                   xfs     defaults        0 0UUID=cbf33183-93bf-4b4f-81c0-ea6ae91cd4f6 /usr                    xfs     defaults        0 0UUID=5e11b173-f7e2-4994-95b9-55cc4c41f20b swap                    swap    defaults        0 0[root@localhost testdir]# mdadm /dev/md0 -r /dev/sdd1    //模拟拔出硬盘[root@localhost testdir]# mdadm -D /dev/md0 ..............................省略........................    Number   Major   Minor   RaidDevice State       3       8       65        0      active sync   /dev/sde1    //已经找不到/dev/sdd1       1       8       50        1      active sync   /dev/sdd2       4       8       51        2      active sync   /dev/sdd3[root@localhost testdir]# [root@localhost testdir]# mdadm /dev/md0 -a /dev/sdd1    //模拟增加硬盘mdadm: added /dev/sdd1[root@localhost testdir]# mdadm -D /dev/md0 //查看信息  ..............................省略........................    Number   Major   Minor   RaidDevice State       3       8       65        0      active sync   /dev/sde1       1       8       50        1      active sync   /dev/sdd2       4       8       51        2      active sync   /dev/sdd3       5       8       49        -      spare   /dev/sdd1    /// /dev/sdd1成功增加[root@localhost testdir]# mdadm /dev/md0 -f /dev/sdd2    //因为RAI5 中有校验位，允许其中的一块磁盘损坏掉，通过校验位可以把原来的数据文件给推算出来mdadm: set /dev/sdd2 faulty in /dev/md0       [root@localhost testdir]# mdadm -D /dev/md0 ..............................省略........................    Number   Major   Minor   RaidDevice State       5       8       49        0      active sync   /dev/sdd1       2       0        0        2      removed       4       8       51        2      active sync   /dev/sdd3       1       8       50        -      faulty   /dev/sdd2       3       8       65        -      faulty   /dev/sde1         //这种情况下依然能查看数据文件，不过性能会下降，所以需要立即修复