Use 4 disks on Debian to perform RAID 5 automatically create an alternate drive

I am trying to create a RAID with 4x 2TB disks on Debian 6. I follow the instructions below: http://zackreed.me/articles/38-software-raid -5-in-debian-with-mdadm

I created the raid with the following command: sudo mdadm –create –verbose /dev/md0 –auto = yes –level = 5 –raid-devices = 4 / dev / sdb1 / dev / sdc1 / dev / sdd1 / development / SDE1

After creating RAID, mdadm –detail /dev/md0 shows me:

< pre>/dev/md0:
Version: 1.2
Creation Time: Mon Jun 11 18:14:26 2012
Raid Level: raid5
Array Size: 5860535808 (5589.04 GiB 6001.19 GB)
Used Dev Size: 1953511936 (1863.01 GiB 2000.40 GB)
Raid Devices: 4
Total Devices: 4
Persistence: Superblock is persistent

Update Time: Mon Jun 11 18:14:26 2012
State: clean, degraded
Active Devices: 3
Working Devices: 4
Failed Devices: 0
Spare Devices: 1

Layout: left-symmetric
Chunk Size: 512K

Name: rsserver:0 (local to host rsserver)
UUID: a68c3c99:1ef865e9:5a8a7bdc:64710ed8
Events: 0

Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 8 33 1 active sync /dev/sdc1
2 8 49 2 active sync /dev/sdd1
3 0 0 3 removed

4 8 65-spare /dev/sde1 < p>Why is there a spare drive? I did not create one. I don’t want to use a spare drive.

If you really want a 4-drive Raid5 (see note above), you should be able to use –spare-devices=0 to set the number of spare devices to 0.

I am trying to create one on Debian 6 with 4x 2TB Disk RAID 5. I follow the instructions below: http://zackreed.me/articles/38-software-raid-5-in-debian-with-mdadm

I use the following command Created a raid: sudo mdadm –create –verbose /dev/md0 –auto = yes –level = 5 –raid-devices = 4 /dev/sdb1 /dev/sdc1 /dev/sdd1/development/SDE1

After creating RAID, mdadm –detail /dev/md0 shows me:

/dev/md0:
 Version: 1.2
 Creation Time: Mon Jun 11 18:14:26 2012
 Raid Level: raid5
 Array Size: 5860535808 (5589.04 GiB 6001.19 GB)
 Used Dev Size: 1953511936 (1863.01 GiB 2000.40 GB)
 Raid Devices: 4
 Total Devices: 4
 Persistence: Superblock is persistent

Update Time: Mon Jun 11 18:14:26 2012
 State: clean, degraded
Active Devices: 3
Working Devices: 4
Failed Devices: 0
Spare Devices: 1

 Layout: left-symmetric
 Chunk Size: 512K

 Name: rsserver:0 (local to host rsserver)
 UUID: a68c3c99:1ef865e9:5a8a7bdc:64710ed8
 Events : 0

Number Major Minor RaidDevice State
 0 8 17 0 active sync /dev/sdb1
 1 8 33 1 active sync /dev/sdc1
 2 8 49 2 active sync /dev/sdd1
 3 0 0 3 removed

 4 8 65-spare /dev/sde1

Why is there a spare drive? I didn’t create one. I don’t want to use a spare drive.

If you really want a Raid5 with 4 drives (see note above), you should be able to use –Spare-devices = 0 Set the number of spare devices to 0.

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