What to do with dead raid 1 partitions under mdadm

[mett <mett@pmars.jp>]

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Hi, 

I'm running Squeeze under raid 1 with mdadm.
One of the raid failed and I replace it with space I had available on
that same disk.

Today, when rebooting I got an error cause the boot flag was still on
both partitions(sdb1 and sdb3 below). I used the rescue part of the
debian installer CD to remove the boot flag with fdisk, and now
everything is working.

My question is what to do with the dead raid partition on that disk
(sdb1 and sdb2 below)?

Can I safely delete them and mark them unusable or similar?

Below are some details about the system.

/dev/sdb is 250G; I had an sdb1 and sdb2 failure. I
created sdb3 and sdb4 and add them to the array. They are the current
member of the md array.

/mett# uname -a
Linux asus 3.2.0-0.bpo.4-686-pae #1 SMP Debian 3.2.57-3+deb7u2~bpo60+1
i686 GNU/Linux 

root@asus:/home/mett# 
root@asus:/home/mett# mdadm --detail /dev/md1
/dev/md1:
        Version : 1.2
  Creation Time : Mon Feb  4 22:46:04 2013
     Raid Level : raid1
     Array Size : 97654712 (93.13 GiB 100.00 GB)
  Used Dev Size : 97654712 (93.13 GiB 100.00 GB)
   Raid Devices : 2
  Total Devices : 2
    Persistence : Superblock is persistent

    Update Time : Sun Oct 26 12:03:37 2014
          State : clean 
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

           Name : asus:1  (local to host asus)
           UUID : 639af1ab:8ec418b5:8254ef0d:ad9a728d
         Events : 75946

    Number   Major   Minor   RaidDevice State
       2       8        2        0      active sync   /dev/sda2
       3       8       20        1      active sync   /dev/sdb4

(/dev/md0 is same structure as above with sda1 and sdb3 as raid members)


root@asus:/home/mett# 
Disk /dev/sdb: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00066b3e

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1          64      514048+  fd  Linux raid
   autodetect 
/dev/sdb2              65       12515   100012657+  fd	Linux
   raid  
   autodetect 
/dev/sdb3   *       12516       12581   530145   fd  Linux raid
   autodetect 
/dev/sdb4           12582       25636   104864287+  fd  Linux raid
   autodetect

Command (m for help): 

Thanks a lot in advance.
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