I have 4 drives, 2x640GB, and 2x1TB drives. My array is made up of the four 640GB partitions and the beginning of each drive. I want to replace both 640GB with 1TB drives. I understand I need to 1) fail a disk 2) replace with new 3) partition 4) add disk to array

My question is, when I create the new partition on the new 1TB drive, do I create a 1TB "Raid Auto Detect" partition? Or do I create another 640GB partition and grow it later?

Or perhaps the same question could be worded: after I replace the drives how to I grow the 640GB raid partitions to fill the rest of the 1TB drive?

fdisk info:

Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xe3d0900f

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1       77825   625129281   fd  Linux raid autodetect
/dev/sdb2           77826      121601   351630720   83  Linux

Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xc0b23adf

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1       77825   625129281   fd  Linux raid autodetect
/dev/sdc2           77826      121601   351630720   83  Linux

Disk /dev/sdd: 640.1 GB, 640135028736 bytes
255 heads, 63 sectors/track, 77825 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x582c8b94

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1       77825   625129281   fd  Linux raid autodetect

Disk /dev/sde: 640.1 GB, 640135028736 bytes
255 heads, 63 sectors/track, 77825 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xbc33313a

   Device Boot      Start         End      Blocks   Id  System
/dev/sde1               1       77825   625129281   fd  Linux raid autodetect

Disk /dev/md0: 1920.4 GB, 1920396951552 bytes
2 heads, 4 sectors/track, 468846912 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk identifier: 0x00000000