How to add virtual hard disk parmanentally in raid 5, if one HDD is demage, then remove that HD and add new HD in raid 5....that is added and data sirnk in that new add HD, but when i restart my syteme, in that case, new add HD is removed, why.............plz help......
[root@localhost ~]# mdadm -a /dev/md0 /dev/sdf1
mdadm: re-added /dev/sdf1
[root@localhost ~]# mdadm -D /dev/md0
/dev/md0:
Version : 0.90
Creation Time : Thu May 31 12:28:41 2012
Raid Level : raid5
Array Size : 10474112 (9.99 GiB 10.73 GB)
Used Dev Size : 5237056 (4.99 GiB 5.36 GB)
Raid Devices : 3
Total Devices : 3
Preferred Minor : 0
Persistence : Superblock is persistent

Update Time : Sat Jun 9 11:22:30 2012
State : clean, degraded, recovering
Active Devices : 2
Working Devices : 3
Failed Devices : 0
Spare Devices : 1

Layout : left-symmetric
Chunk Size : 64K

Rebuild Status : 18% complete

UUID : fedca1e1:e9dd085a:39dd7baa:7c403756
Events : 0.144

Number Major Minor RaidDevice State
0 8 81 0 spare rebuilding /dev/sdf1
1 8 49 1 active sync /dev/sdd1
2 8 65 2 active sync /dev/sde1
[root@localhost ~]# mdadm -D /dev/md0
/dev/md0:
Version : 0.90
Creation Time : Thu May 31 12:28:41 2012
Raid Level : raid5
Array Size : 10474112 (9.99 GiB 10.73 GB)
Used Dev Size : 5237056 (4.99 GiB 5.36 GB)
Raid Devices : 3
Total Devices : 3
Preferred Minor : 0
Persistence : Superblock is persistent

Update Time : Sat Jun 9 11:53:03 2012
State : clean
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0

Layout : left-symmetric
Chunk Size : 64K

UUID : fedca1e1:e9dd085a:39dd7baa:7c403756
Events : 0.146

Number Major Minor RaidDevice State
0 8 81 0 active sync /dev/sdf1
1 8 49 1 active sync /dev/sdd1
2 8 65 2 active sync /dev/sde1


NOTE:::::::::
Now new HDD is addd, but, when i restart my pc, and i got that added HDD is removed, why..plz help..........

[root@localhost ~]# init 6

[root@localhost ~]# mdadm -D /dev/md0
/dev/md0:
Version : 0.90
Creation Time : Thu May 31 12:28:41 2012
Raid Level : raid5
Array Size : 10474112 (9.99 GiB 10.73 GB)
Used Dev Size : 5237056 (4.99 GiB 5.36 GB)
Raid Devices : 3
Total Devices : 2
Preferred Minor : 0
Persistence : Superblock is persistent

Update Time : Sat Jun 9 11:22:30 2012
State : clean, degraded
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0

Layout : left-symmetric
Chunk Size : 64K

UUID : fedca1e1:e9dd085a:39dd7baa:7c403756
Events : 0.144

Number Major Minor RaidDevice State
0 0 0 0 removed
1 8 49 1 active sync /dev/sdd1
2 8 65 2 active sync /dev/sde1

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