Tag Archive for 'soft raid'

RAID1 replace broken HDD

Published on September 5, 2011 15:58 Tags: , , , , .

If you see something like this on your monitor or in your logs, you should worry about your important data.

And immediately change your HDD!

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ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
ata1.00: failed command: FLUSH CACHE EXT
ata1.00: cmd ea/00:00:00:00:00/00:00:00:00:00/a0 tag 0
res 40/00:0c:b9:68:55/00:00:05:00:00/40 Emask 0x4 (timeout)
ata1.00: status: { DRDY }
ata1: hard resetting link
ata1: link is slow to respond, please be patient (ready=0)
ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata1.00: configured for UDMA/133
ata1: EH complete

Continue reading ‘RAID1 replace broken HDD’

Setting up Soft RAID

Published on August 27, 2010 23:07 Tags: , , , , , , .

This is a very quick guide to setting up a Linux software RAID.

All these examples are same for RAID0 and RAID1

0. Disclaimer
Make sure you back up all your data, or you have empty hdds before you proceed.

1. Disk management
I’m using 2 same HDDs with 400Gigs.

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Disk /dev/sdb: 400.0 GB, 400088457216 bytes
Disk /dev/sdc: 400.0 GB, 400088457216 bytes

I created on both disks new partitions with parted (also you can use gparted):

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/dev/sdb1               1       48641   390708801   83  Linux
/dev/sdc1               1       48641   390708801   83  Linux


2. Raid creation

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$ aptitude update
$ aptitude install mdadm

For RAID-0

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$ mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sdb1 /dev/sdc1

For RAID-1

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$ mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1

3. Get RAID information

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$ fdisk -l
Disk /dev/md0: 800.1 GB, 800171491328 bytes
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$ cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid0 sdc1[1] sdb1[0]
      781417472 blocks 64k chunks
 
unused devices: <none>
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$ mdadm --detail --scan
ARRAY /dev/md0 level=raid0 num-devices=2 metadata=00.90 UUID=fb3d1fd3:5dd2b871:01f9e43d:ac30fbff
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$ mdadm --detail /dev/md0 
/dev/md0:
        Version : 00.90
  Creation Time : Fri Aug 27 21:27:51 2010
     Raid Level : raid0
     Array Size : 781417472 (745.22 GiB 800.17 GB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 0
    Persistence : Superblock is persistent
 
    Update Time : Fri Aug 27 22:46:13 2010
          State : active
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0
 
     Chunk Size : 64K
 
           UUID : fb3d1fd3:5dd2b871:2ce552e4:6d63ea58
         Events : 0.3
 
    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1

4. Create file system
That all you have a running RAID array, to use it you need to create a filesystem for example ext3 one.

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mkfs.ext3 /dev/md0

Delete RAID array:

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mdadm --stop /dev/md0

To make sure it doesn’t come back, you need to delete the RAID super blocks…

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mdadm --misc --zero-superblock /dev/sdb1
mdadm --misc --zero-superblock /dev/sdc1

You can mount your raid partition automatically on server start:

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vim /etc/fstab

And add this line to it:

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/dev/md0        /mnt           ext3    defaults    0   0

md0 will automatically mounted to /mnt/

Start a partially built array:

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$ mdadm --run /dev/md0
 
 
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid1 sdb1[0] sdc1[1]
      390708736 blocks [2/2] [UU]
      [>....................]  resync =  0.0% (277568/390708736) finish=70.3min speed=92522K/sec

Don’t forget the RAM usage: