Linux运维学习-磁盘管理之磁盘冗余阵列(RAID)
RAID实现方式:
硬RAID:企业常用,专门购买RAID卡,调试通过类似BIOS系统的页面
软RAID:与硬RAID原理上完全一样,通过mdadm命令控制RAID创建、修改、删除等操作
RAID种类:
RIAD0:
RAID-0 ,又叫striping,至少需要两块硬盘,只注重速率,硬盘读写的速率,没有任何的数据冗余措施(如果某个block坏了,数据丢失),但是磁盘利用率是100%
RAID1:
RAID-1,又叫mirroring,至少两块盘,速度并没有提升,磁盘使用率 1/n,但是提供了数据冗余,两块盘数据完全一样(只要我们不是同时损坏同一处数据),都可以恢复
RAID10:
RAID-1为底层,RAID-0为上层,不能同时损坏RAID1中的同一个block
RAID01:
与RAID10相似,RAID-0为底层,RAID-1为上层。
RAID5:企业常用
RAID-5至少需要三块盘,至多损坏一块,硬盘使用率 (n-1)/n,单奇偶校验
RAID6:企业常用
RAID-6 至少四块盘,至多损坏两块,使用率(n-2)/n,双奇偶校验码
mdadm命令:RAID的创建、模拟损坏、修复、删除
[[email protected] ~]# ls -l /dev/sd* brw-rw----. 1 root disk 8, 0 Mar 21 03:13 /dev/sda brw-rw----. 1 root disk 8, 1 Mar 21 03:13 /dev/sda1 brw-rw----. 1 root disk 8, 2 Mar 21 03:13 /dev/sda2 brw-rw----. 1 root disk 8, 16 Mar 21 03:13 /dev/sdb brw-rw----. 1 root disk 8, 32 Mar 21 03:13 /dev/sdc brw-rw----. 1 root disk 8, 48 Mar 21 03:13 /dev/sdd brw-rw----. 1 root disk 8, 64 Mar 21 03:13 /dev/sde brw-rw----. 1 root disk 8, 80 Mar 21 03:13 /dev/sdf [[email protected] ~]#
创建RAID5:同时创建备份盘
创建RAID5: [[email protected] ~]# mdadm -Cv /dev/md0 -n3 -x1 -l5 -a yes /dev/sd[b-d] /dev/sdf mdadm: layout defaults to left-symmetric mdadm: layout defaults to left-symmetric mdadm: chunk size defaults to 512K mdadm: size set to 20955136K mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md0 started. [[email protected] ~]#
[[email protected] ~]# mdadm -D /dev/md0 /dev/md0: Version : 1.2 Creation Time : Thu Mar 21 03:17:33 2019 Raid Level : raid5 Array Size : 41910272 (39.97 GiB 42.92 GB) Used Dev Size : 20955136 (19.98 GiB 21.46 GB) Raid Devices : 3 Total Devices : 4 Persistence : Superblock is persistent Update Time : Thu Mar 21 03:19:19 2019 State : clean Active Devices : 3 Working Devices : 4 Failed Devices : 0 Spare Devices : 1 Layout : left-symmetric Chunk Size : 512K Name : localhost.localdomain:0 (local to host localhost.localdomain) UUID : 6480c0ab:cf2025e7:e90b1e1d:db187e1d Events : 18 Number Major Minor RaidDevice State 0 8 16 0 active sync /dev/sdb 1 8 32 1 active sync /dev/sdc 4 8 48 2 active sync /dev/sdd 3 8 80 - spare /dev/sdf [[email protected] ~]#
创建文件系统及挂载: [[email protected] ~]# mkfs.xfs /dev/md0 meta-data=/dev/md0 isize=512 agcount=16, agsize=654720 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0, sparse=0 data = bsize=4096 blocks=10475520, imaxpct=25 = sunit=128 swidth=256 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=1 log =internal log bsize=4096 blocks=5120, version=2 = sectsz=512 sunit=8 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 [[email protected] ~]# [[email protected] ~]# mkdir /backup1 [[email protected] ~]# [[email protected] ~]# mount /dev/md0 /backup1/ [[email protected] ~]# [[email protected] ~]# df -h /dev/md0 Filesystem Size Used Avail Use% Mounted on /dev/md0 40G 33M 40G 1% /backup1 [[email protected] ~]#
模拟磁盘损坏: [[email protected] ~]# mdadm /dev/md0 -f /dev/sdc mdadm: set /dev/sdc faulty in /dev/md0 [[email protected] ~]# [[email protected] ~]# mdadm -D /dev/md0 /dev/md0: Version : 1.2 Creation Time : Thu Mar 21 03:17:33 2019 Raid Level : raid5 Array Size : 41910272 (39.97 GiB 42.92 GB) Used Dev Size : 20955136 (19.98 GiB 21.46 GB) Raid Devices : 3 Total Devices : 4 Persistence : Superblock is persistent Update Time : Thu Mar 21 03:25:22 2019 State : clean Active Devices : 3 Working Devices : 3 Failed Devices : 1 Spare Devices : 0 Layout : left-symmetric Chunk Size : 512K Name : localhost.localdomain:0 (local to host localhost.localdomain) UUID : 6480c0ab:cf2025e7:e90b1e1d:db187e1d Events : 37 Number Major Minor RaidDevice State 0 8 16 0 active sync /dev/sdb 3 8 80 1 active sync /dev/sdf 4 8 48 2 active sync /dev/sdd 1 8 32 - faulty /dev/sdc [[email protected] ~]#