Two 30 GB hard disks for RAID 1

In this experiment, we need to add two new 30 GB hard disks.

[[Email protected] ~] # Uname-

Linux zzsrv1.localdomain 3.10.0-123. el7.x86 _ 64 #1 SMP mon Jun 30 12:09:22 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

We can display the disk without restarting it.

[[Email protected] ~] # Echo "---">/sys/class/scsi_host/host0/scan

[[Email protected] ~] # Echo "---">/sys/class/scsi_host/host1/scan

[[Email protected] ~] # Echo "---">/sys/class/scsi_host/host2/scan

View Disks

[[Email protected] ~] # Fdisk-l

Disk/dev/SDA: 42.9 GB, 42949672960 bytes, 83886080 sectors

Units = sectors of 1*512 = 512 bytes

Sector size (logical/physical): 512 bytes/512 bytes

I/O size (minimum/optimal): 512 bytes/512 bytes

Disk label type: DoS

Disk identifier: 0x0003747c

Device boot start end blocks ID system

/Dev/sda1*2048 1026047 512000 83 Linux

/Dev/sda2 1026048 83886079 41430016 8e Linux LVM

Disk/dev/SDB: 32.2 GB, 32212254720 bytes, 62914560 sectors

Units = sectors of 1*512 = 512 bytes

Sector size (logical/physical): 512 bytes/512 bytes

I/O size (minimum/optimal): 512 bytes/512 bytes

Disk/dev/SDC: 32.2 GB, 32212254720 bytes, 62914560 sectors

Units = sectors of 1*512 = 512 bytes

Sector size (logical/physical): 512 bytes/512 bytes

I/O size (minimum/optimal): 512 bytes/512 bytes

Install mdadm

[[Email protected] ~] # Mount/dev/CDROM/mnt/CDROM/

[[Email protected] ~] # Cd/mnt/CDROM/packages/

[[Email protected] packages] # ls mdadm *

Mdadm-3.2.6-31.el7.x86_64.rpm

[[Email protected] packages] # rpm-IVH mdadm-3.2.6-31.el7.x86_64.rpm

Warning: mdadm-3.2.6-31.el7.x86_64.rpm: Header V3 RSA/sha256 signature, key ID f4a80eb5: nokey

Preparing... ################################### [100%]

Package mdadm-3.2.6-31.el7.x86_64 is already installed

Partition a disk

[[Email protected] packages] # fdisk/dev/SDB

[[Email protected] packages] # fdisk/dev/SDC

Create raid1 volume

[[Email protected] ~] # Mdadm-CV/dev/md0-L1-N2/dev/sdc1/dev/sdb1

Mdadm:/dev/sdc1 appears to contain an ext2fs File System

Size = 31456256 K mtime = Thu Jan 1 08:00:00 1970

Mdadm: Note: This array has metadata at the start and

May not be suitable as a boot device. If you plan

Store'/boot' on this device please ensure that

Your boot-loader understands MD/v1.x metadata, or use

-- Metadatabase = 0.90

Mdadm:/dev/sdb1 appears to contain an ext2fs File System

Size = 31456256 K mtime = Thu Jan 1 08:00:00 1970

Mdadm: size set to 31439744 K

Continue creating array? (Y/n) y

Mdadm: defaulting to version 1.2 metadata

Mdadm: array/dev/md0 started.

[[Email protected] ~] # Cd/

[[Email protected]/] # Cat/proc/mdstat

Personalities: [raid1]

Md0: Active raid1 sdb1 [1] sdc1 [0]

31439744 blocks super 1.2 [2/2] [UU]

[========> ...... Resync = 41.6% (13101184/31439744) finish = 1.5 min speed = 199772 K/sec

Unused devices: <none>

Format a raid volume

[[Email protected] packages] # mkfs. ext4/dev/md0

Mke2fs 1.42.9 (28-dec-2013)

Filesystem label =

OS type: Linux

Block size = 4096 (log = 2)

Fragment size = 4096 (log = 2)

Stride = 0 blocks, stripe width = 0 blocks

1310720 inodes, 5238496 Blocks

261924 blocks (5.00%) reserved for the Super User

First data block = 0

Maximum filesystem blocks = 2153775104

160 block groups

32768 blocks per group, 32768 fragments per group

8192 inodes per group

Superblock backups stored on blocks:

32768,983 04, 163840,229 376, 294912,819 200, 884736,160 5632, 2654208,

4096000

Allocating group tables: Done

Writing inode tables: Done

Creating Journal (32768 blocks): Done

Writing superblocks and filesystem accounting information: Done

[[Email protected] packages] # mkdir/Data

[[Email protected] packages] # Mount/dev/md0/Data

[[Email protected] packages] # ll/data/

Total 16

Drwx ------ 2 root Root 16384 Aug 15:31 lost + found

[[Email protected] packages] # mdadm-Ds

Array/dev/md0 metadata = 1.2 name = zzsrv1.localdomain: 0 UUID = c2fe6a35: 461511e9: 7e9bf672: 9baeb95c

[[Email protected] packages] # mdadm-DS>/etc/mdadm. conf

[[Email protected] packages] # vi/etc/fstab

Add at last

/Dev/md0/Data ext4 defaults 0 0

[[Email protected] packages] # mdadm-Ds

Array/dev/md0 metadata = 1.2 name = zzsrv1.localdomain: 0 UUID = c2fe6a35: 461511e9: 7e9bf672: 9baeb95c

[[Email protected] packages] # mdadm-DS>/etc/mdadm. conf

[[Email protected] packages] # reboot

[[Email protected] ~] # Mount

/Dev/mapper/VolGroup-lv_root on/type ext4 (RW)

Proc on/proc type proc (RW)

Sysfs on/sys type sysfs (RW)

Devpts on/dev/PTS type devpts (RW, gid = 5, mode = 620)

Tmpfs on/dev/SHM type tmpfs (RW)

/Dev/sda1 on/boot type ext4 (RW)

/Dev/md0 on/Data Type ext4 (RW)

None on/proc/sys/fs/binfmt_misc type binfmt_misc (RW)

[[Email protected] ~] # Cat/proc/mdstat

Personalities: [raid1]

Md0: Active raid1 sdb1 [0] sdc1 [1]

31438720 blocks super 1.2 [2/2] [UU]

Unused devices: <none>

We can simulate faults.

Delete A 30 GB hard disk

It may take a while to view the log

SD 2: 0: 1: 0: [SDB] unhandled error code

SD 2: 0: 1: 0: [SDB] Result: hostbyte = did_no_connect driverbyte = driver_ OK

SD 2: 0: 1: 0: [SDB] CDB: Write (10): 2a 00 00 00 00 47 00 00 01 00

MD: super_written gets error =-5, uptodate = 0

MD/raid1: md0: disk failure on sdb1, disabling device.

MD/raid1: md0: Operation Continuing on 1 devices.

Raid1 conf printout:

--- WD: 1 RD: 2

Disk 0, Wo: 1, O: 0, Dev: sdb1

Disk 1, Wo: 0, O: 1, Dev: sdc1

Raid1 conf printout:

--- WD: 1 RD: 2

Disk 1, Wo: 0, O: 1, Dev: sdc1

SD 2: 0: 1: 0: [SDB] unhandled error code

SD 2: 0: 1: 0: [SDB] Result: hostbyte = did_no_connect driverbyte = driver_ OK

SD 2: 0: 1: 0: [SDB] CDB: Write (10): 2a 00 00 00 00 47 00 00 01 00

MD: super_written gets error =-5, uptodate = 0

MD/raid1: md0: disk failure on sdb1, disabling device.

MD/raid1: md0: Operation Continuing on 1 devices.

[[Email protected] ~] # Cat/proc/mdstat

Personalities: [raid1]

Md0: Active raid1 sdb1 [0] (f) sdc1 [1]

31438720 blocks super 1.2 [2/1] [_ u]

Unused devices: <none>

If a fault occurs, we need to reconstruct raid1.

Simulate recovery and add a new 30 GB hard disk

[[Email protected] ~] # Fdisk-L/dev/SDB

Disk/dev/SDB: 32.2 GB, 32212254720 bytes

255 heads, 63 sectors/track, 3916 Cylinders

Units = cylinders of 16065*512 = 8225280 bytes

Sector size (logical/physical): 512 bytes/512 bytes

I/O size (minimum/optimal): 512 bytes/512 bytes

Disk identifier: 0x9b6ff607

Device boot start end blocks ID system

/Dev/sdb1 2048 62914559 31456256 83 Linux

Add new component online

[[Email protected] ~] # Mdadm/dev/md0-A/dev/sdb1

Mdadm: added/dev/sdb1

[[Email protected] ~] # Cat/proc/mdstat

Personalities: [raid1]

Md0: Active raid1 sdb1 [2] sdc1 [1]

31438720 blocks super 1.2 [2/1] [_ u]

[=> ......] Recovery = 7.0% (2201920/31438720) finish = 2.4 min speed = 200174 K/sec

Unused devices: <none>

In the log, we can see the reconstruction process.

MD: bind <sdb1>

MD: Recovery of RAID array md0

MD: Minimum _ guaranteed _ speed: 1000 kb/SEC/disk.

MD: using maximum available idle Io bandwidth (but not more than 200000 KB/sec) for recovery.

MD: Using 128 K window, over a total of 31438720 K.

MD: md0: Recovery done.