I'm trying to build a simple Raid 5 array out of 4 SATA drives. They dries are , 250GB, 250GB, 500GB and 500GB. I've created partitions on each of them that are the exact same size, roughly 250GB.

/dev/sda1, /dev/sdb1. /dev/sdc1, /dev/sdd1

I created an array on these partiions before, but after a power outage it just died. not sure why...but since there was little of value on there, I just decided to rebuild the set from scratch. I first tried...

mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1

The device would start and then begin rebuilding as normal...about 5 minutes later it would show up like this.

+++++++++++++++++++++++++++++++++++++++
Version : 00.90.03
Creation Time : Wed Jan 16 21:03:10 2008
Raid Level : raid5
Array Size : 732563712 (698.63 GiB 750.15 GB)
Used Dev Size : 244187904 (232.88 GiB 250.05 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Persistence : Superblock is persistent

Update Time : Wed Jan 16 21:05:22 2008
State : clean, degraded
Active Devices : 2
Working Devices : 3
Failed Devices : 1
Spare Devices : 1

Layout : left-symmetric
Chunk Size : 64K

UUID : 26ab635c:6dcc91db:645e3c10:269b8dbf
Events : 0.34

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

4 8 49 - spare /dev/sdd1
5 8 1 - faulty spare /dev/sda1

+++++++++++++++++++++++++++++++++++++
So it looks like 2 drives are faulty...but I can't see that they are. I have tested both of the drives and they appear fine. I can mount them and use them as individual drives, but in the raid set it's not working.

I tried zeroing the superblocks on each and I've repartitioned each of the drives. still the same result.

any help is appreciated.