Linux – Hard disk error

There seems to be something wrong with my hard drive, but I'm not sure what, or how to proceed. The first sign of any problems was this:

I tried making a new directory on my server, but when I did so, it hung for like 30 seconds, then gave this error:

root@smallgames:~# mkdir derpherp
mkdir: cannot create directory `derpherp': Input/output error
Message from syslogd@smallgames at May  1 18:09:17 ...
 kernel:[8731601.569393] journal commit I/O error

I then tried running fsck:

root@smallgames:~# fsck
fsck from util-linux 2.20.1
e2fsck 1.41.12 (17-May-2010)
/dev/vda1: recovering journal
fsck.ext3: Bad magic number in super-block while trying to re-open /dev/vda1
e2fsck: io manager magic bad!

Running it again gives this:

root@smallgames:~# fsck
fsck from util-linux 2.20.1
fsck.ext3: Unable to resolve 'UUID=e4565c70-2bcd-40c8-ac8a-dab5bab4167c'

Running ls on anything now gives me an empty directory.
This is Debian running in a VM in Proxmox.

Running dmesg on the main server gives a lot of these:

ata1.00: exception Emask 0x0 SAct 0x1 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:00:b9:c1:34/00:00:3f:00:00/40 tag 0 ncq 4096 in
         res 41/40:08:c0:c1:34/00:00:3f:00:00/00 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete

Output of mdadm --detail /dev/md*:

root@ks212866:~# mdadm --detail /dev/md*
mdadm: /dev/md does not appear to be an md device
/dev/md1:
        Version : 0.90
  Creation Time : Sat Nov  3 22:07:42 2012
     Raid Level : raid1
     Array Size : 10485696 (10.00 GiB 10.74 GB)
  Used Dev Size : 10485696 (10.00 GiB 10.74 GB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 1
    Persistence : Superblock is persistent

    Update Time : Wed May  1 21:42:44 2013
          State : clean, degraded
 Active Devices : 1
Working Devices : 1
 Failed Devices : 1
  Spare Devices : 0

           UUID : da7935e9:ed88ed4b:a4d2adc2:26fd5302
         Events : 0.67258

    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       0        0        1      removed

       2       8       17        -      faulty spare   /dev/sdb1
/dev/md2:
        Version : 0.90
  Creation Time : Sat Nov  3 22:07:43 2012
     Raid Level : raid1
     Array Size : 965746624 (921.01 GiB 988.92 GB)
  Used Dev Size : 965746624 (921.01 GiB 988.92 GB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 2
    Persistence : Superblock is persistent

    Update Time : Wed May  1 21:42:59 2013
          State : clean, degraded
 Active Devices : 1
Working Devices : 1
 Failed Devices : 1
  Spare Devices : 0

           UUID : 70302f6a:598cdf5f:a4d2adc2:26fd5302
         Events : 0.351218

    Number   Major   Minor   RaidDevice State
       0       8        2        0      active sync   /dev/sda2
       1       0        0        1      removed

       2       8       18        -      faulty spare   /dev/sdb2