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企业经常用到的RAID+LVM管理模式的建立： 用到的软件：VMware Workstation 10 系统环境： [root@localhost~]# cat /etc/centos-release CentOSLinux release 7.0.1406 (Core) [root@localhost~]# rpm -qi mdadm Name : mdadm Version : 3.2.6 RAID 1+0方案简介先对磁盘做mirror，然后对整个mirror组做条带化；比如8块盘需要分成4个基组，每个基组2块盘；每个基组先做raid1，再做raid0，4条条带化。 所以： 允许所有磁盘基组中的磁盘各损坏一个，但是不允许同一基组中的磁盘同时有坏的。 优点：数据安全性好，只要不是1个条带上的2个硬盘同时坏，没有问题，还可以继续跑数据。数据恢复快。 缺点 ：写性能稍微比RAID 0+1 差（读性能一样）
我的思路 在新添加的硬盘上划分4个1G的区域分别为1,2,3,5 每两个转化为一个RAID 1 卷 /dev/md{1,2} 将这两个RAID 1 卷转化为一个RAID 0卷/dev/md0 将RAID 0转化为pv，vg 之后通过lv创建自己的空间 这个空间就具有RAID 1+0的性质
详细实施过程
我们这里添加一块用作实验的硬盘2 我们不想重启来读取新添加的硬盘，我们输入下面命令进行扫描 [root@localhost~]# echo "- - -" > /sys/class/scsi_host/host0/scan [root@localhost~]# echo "- - -" > /sys/class/scsi_host/host1/scan [root@localhost~]# echo "- - -" > /sys/class/scsi_host/host2/scan [root@localhost~]# fdisk -l Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040sectors Units= sectors of 1 * 512 = 512 bytes Sectorsize (logical/physical): 512 bytes / 512 bytes I/Osize (minimum/optimal): 512 bytes / 512 bytes 发现新添加的sdb
下面开始具体的实验过程 #fdisk/dev/sdb Command(m for help): n Partitiontype: p primary (0 primary, 0 extended, 4 free) e extended Select(default p): Usingdefault response p Partitionnumber (1-4, default 1): Firstsector (2048-41943039, default 2048): Usingdefault value 2048 Lastsector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +1G Partition1 of type Linux and of size 1 GiB is set Command(m for help): n Partitiontype: p primary (1 primary, 0 extended, 3 free) e extended Select(default p): Usingdefault response p Partitionnumber (2-4, default 2): Firstsector (2099200-41943039, default 2099200): Usingdefault value 2099200 Lastsector, +sectors or +size{K,M,G} (2099200-41943039, default 41943039): +1G Partition2 of type Linux and of size 1 GiB is set Command(m for help): n Partitiontype: p primary (2 primary, 0 extended, 2 free) e extended Select(default p): Usingdefault response p Partitionnumber (3,4, default 3): Firstsector (4196352-41943039, default 4196352): Usingdefault value 4196352 Lastsector, +sectors or +size{K,M,G} (4196352-41943039, default 41943039): +1G Partition3 of type Linux and of size 1 GiB is set Command(m for help): n Partitiontype: p primary (3 primary, 0 extended, 1 free) e extended Select (default e): Usingdefault response e Selectedpartition 4 Firstsector (6293504-41943039, default 6293504): Usingdefault value 6293504 Lastsector, +sectors or +size{K,M,G} (6293504-41943039, default 41943039): Usingdefault value 41943039 Partition4 of type Extended and of size 17 GiB is set 将剩余的所有空间划给扩展区，之后再划分区间用l命令即逻辑盘区 此后的区间号就从5开始往后加 Command(m for help): n Allprimary partitions are in use Addinglogical partition 5 Firstsector (6295552-41943039, default 6295552): Usingdefault value 6295552 Lastsector, +sectors or +size{K,M,G} (6295552-41943039, default 41943039): +1G Partition5 of type Linux and of size 1 GiB is set Command(m for help): p
Disk/dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors Units= sectors of 1 * 512 = 512 bytes Sectorsize (logical/physical): 512 bytes / 512 bytes I/Osize (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Diskidentifier: 0x8e9a9326
Device Boot Start End Blocks Id System /dev/sdb1 2048 2099199 1048576 83 Linux /dev/sdb2 2099200 4196351 1048576 83 Linux /dev/sdb3 4196352 6293503 1048576 83 Linux /dev/sdb4 6293504 41943039 17824768 5 Extended /dev/sdb5 6295552 8392703 1048576 83 Linux /dev/sdb6 8394752 10491903 1048576 83 Linux [root@localhost ~]# mdadm -C /dev/md1-a yes -l 1 -n 2 /dev/sdb{1,2} mdadm:Note: this array has metadata at the start and may not be suitable as a boot device. If you plan to store '/boot' on this device please ensurethat your boot-loader understands md/v1.xmetadata, or use --metadata=0.90 Continuecreating array? Continuecreating array? (y/n) y mdadm:Defaulting to version 1.2 metadata mdadm:array /dev/md1 started. [root@localhost ~]# mdadm -C /dev/md2 -a yes-l 1 -n 2 /dev/sdb{3,5} mdadm:Note: this array has metadata at the start and may not be suitable as a boot device. If you plan to store '/boot' on this device please ensurethat your boot-loader understands md/v1.xmetadata, or use --metadata=0.90 Continuecreating array? Continuecreating array? (y/n) y mdadm:Defaulting to version 1.2 metadata mdadm:array /dev/md2 started. [root@localhost ~]# mdadm -C /dev/md0 -a yes-l 1 -n 2 /dev/md{1,2}（将RAID1转化为RAID0） mdadm:Note: this array has metadata at the start and may not be suitable as a boot device. If you plan to store '/boot' on this device please ensurethat your boot-loader understands md/v1.xmetadata, or use --metadata=0.90 Continuecreating array? Continuecreating array? (y/n) y mdadm:Defaulting to version 1.2 metadata mdadm:array /dev/md0 started. [root@localhost ~]# pvcreate /dev/md0（变PV） Physical volume "/dev/md0"successfully created [root@localhost ~]# vgcreate first/dev/md0（变VG） Volume group "first" successfullycreated [root@localhost~]# lvcreate -L 1G -n data1 first Volume group "first" hasinsufficient free space (255 extents): 256 required. [root@localhost ~]# lvcreate -L +500M-n data1 first（划分自己想要的区域大小） Logical volume "data1" created
[root@localhost ~]# mkfs.ext4/dev/first/data1（格式化） mke2fs1.42.9 (28-Dec-2013) Filesystemlabel= OStype: Linux Blocksize=1024 (log=0) Fragmentsize=1024 (log=0) Stride=0blocks, Stripe width=0 blocks 128016inodes, 512000 blocks 25600blocks (5.00%) reserved for the super user Firstdata block=1 Maximumfilesystem blocks=34078720 63block groups 8192blocks per group, 8192 fragments per group 2032inodes per group Superblockbackups stored on blocks: 8193, 24577, 40961, 57345, 73729,204801, 221185, 401409
Allocatinggroup tables: done Writinginode tables: done Creatingjournal (8192 blocks): done Writingsuperblocks and filesystem accounting information: done
[root@localhost~]# mkdir /lvm1 [root@localhost~]# mount /dev/first/data1 /lvm1 [root@localhost~]# cd /lvm1 [root@localhostlvm1]# ll total12 drwx------2 root root 12288 Aug 12 21:21 lost+found 挂载后即可对划分出的新空间进行使用。 举例这里举个例子，20个硬盘做RAID 1+0，共10个条带，每个条带2个硬盘做MIRROR，如果坏了1个硬盘，没关系，其它19个硬盘还要同时工作，只要不是坏在一个MIRROR里面的，就没事。 建议，硬盘很多时，同时坏的几率就比较大，建议使用安全系数高的RAID 1+0,宁愿损失点性能（其实差不多)。 后语： 新手，如有错误，欢迎指正。 本文出自 “张帆-IT的奇幻漂流” 博客，请务必保留此出处http://chawan.blog.51cto.com/9179874/1540190 (责任编辑：IT) |
