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Raid5 on Debian

Raid5 on Debian 實作全記錄
收入從建立 Raid device
及日後增加硬碟讓空間更大等實作技巧

首先安裝 raidtools2

[root]# apt-get install raidtools2

分割區如下:

[root]# fdisk -l /dev/hde


Disk /dev/hde: 16 heads, 63 sectors, 238216 cylinders

Units = cylinders of 1008 * 512 bytes

   Device Boot    Start       End    Blocks   Id  System

/dev/hde1             1    238216 120060832+  fd  Linux raid autodetect

從設定範例做修改

[root]# cp /usr/share/doc/raidtools2/examples/raid5.conf.sample /etc/raidtab

edit /etc/raidtab

# Sample raid-5 configuration

raiddev                 /dev/md0

raid-level              5

nr-raid-disks           4

chunk-size              256


# Parity placement algorithm

#parity-algorithm       left-asymmetric

#

# the best one for maximum performance:

#

parity-algorithm        left-symmetric

#parity-algorithm       right-asymmetric

#parity-algorithm       right-symmetric

# Spare disks for hot reconstruction

#nr-spare-disks         0

device                  /dev/hde1

raid-disk               0

device                  /dev/hdf1

raid-disk               1

device                  /dev/hdg1

raid-disk               2

建立 Raid

[root]# mkraid /dev/md0

[root]# cfdisk /dev/md0

[root]# mke2fs -j -b 4096 -R stride=64 -m 1 /dev/md0

[root]# cat /proc/mdstat 

Personalities : [raid5] 

read_ahead 1024 sectors

md0 : active raid5 hdg1[2] hdf1[1] hde1[0]

      720364995 blocks level 5, 256k chunk, algorithm 2 [4/4] [UUUU]

      [>....................]  resync =  0.1% (148532/120060736) finish=134.8min speed=11425K/sec

unused devices: 

[root]# mount /dev/md0 /mnt

[root]# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/hda2              13G  347M   12G   3% /

/dev/md0              225G   33M  213G   1% /mnt

若以後空間不夠要加硬碟可以重新設定 Raid device

[root]# cp /etc/raidtab /etc/oldraidtab

[root]# cp /etc/oldraidtab /etc/newraidtab

[root]# /etc/init.d/raid2 stop   

Stopping RAID devices: /dev/md0 done.

[root]# vi newraidtab

[root]# raidreconf -o oldraidtab -n newraidtab -m /dev/md0

Working with device /dev/md0

Parsing oldraidtab

Parsing newraidtab

Size of old array: 720364995 blocks,  Size of new array: 960486660 blocks

Old raid-disk 0 has 468987 chunks, 120060736 blocks

Old raid-disk 1 has 468987 chunks, 120060736 blocks

Old raid-disk 2 has 468987 chunks, 120060736 blocks

New raid-disk 0 has 468987 chunks, 120060736 blocks

New raid-disk 1 has 468987 chunks, 120060736 blocks

New raid-disk 2 has 468987 chunks, 120060736 blocks

New raid-disk 3 has 468987 chunks, 120060736 blocks

Using 256 Kbyte blocks to move from 256 Kbyte chunks to 256 Kbyte chunks.

Detected 126412 KB of physical memory in system

A maximum of 144 outstanding requests is allowed

---------------------------------------------------

I will grow your old device /dev/md0 of 937974 blocks

to a new device /dev/md0 of 1406961 blocks

using a block-size of 256 KB

Is this what you want? (yes/no): yes

Converting 937974 block device to 1406961 block device

Allocated free block map for 3 disks

4 unique disks detected.

Working (-) [00937974/00937974] [############################################] 

Source drained, flushing sink.

Reconfiguration succeeded, will update superblocks...

Updating superblocks...

handling MD device /dev/md0

analyzing super-block

disk 0: /dev/hde1, 120060832kB, raid superblock at 120060736kB

disk 1: /dev/hdf1, 120060832kB, raid superblock at 120060736kB

disk 2: /dev/hdg1, 120060832kB, raid superblock at 120060736kB

disk 3: /dev/hdh1, 120060832kB, raid superblock at 120060736kB

Array is updated with kernel.

Disks re-inserted in array... Hold on while starting the array...

Maximum friend-freeing depth:         4

Total wishes hooked:             937974

Maximum wishes hooked:              144

Total gifts hooked:              937974

Maximum gifts hooked:               107

Congratulations, your array has been reconfigured,

and no errors seem to have occured.

[root]# mount /dev/md0 /backup/

[root]# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/hda2              13G  309M   12G   3% /

/dev/md0              225G   33M  213G   1% /backup

[root]# umount /backup/

[root]# resize2fs /dev/md0

resize2fs 1.27 (8-Mar-2002)

Please run 'e2fsck -f /dev/md0' first.

[root]# e2fsck -f /dev/md0

e2fsck 1.27 (8-Mar-2002)

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Checking reference counts

Pass 5: Checking group summary information

/dev/md0: 11/30015488 files (9.1% non-contiguous), 950095/60030336 blocks

[root]# resize2fs /dev/md0

resize2fs 1.27 (8-Mar-2002)

The filesystem on /dev/md0 is now 90045504 blocks long.

[root]# mount /dev/md0 /backup/

[root]# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/hda2              13G  309M   12G   3% /

/dev/md0              338G   35M  324G   1% /backup

[root]# cat /proc/mdstat 

Personalities : [raid5] 

read_ahead 1024 sectors

md0 : active raid5 hdh1[3] hdg1[2] hdf1[1] hde1[0]

      360182016 blocks level 5, 256k chunk, algorithm 2 [4/4] [UUUU]

      

unused devices: