Remember the golden rule of fsck: Never fsck a mounted filesystem! Always unmount the filesystem before attempting an fsck, or you will lose data. Since the root filesystem cannot be unmounted, you must boot to alternate media (cd-rom or network) to perform the fsck


  1. Drop to the open boot prom
  2. Boot to single user mode from cd-rom or network:
    3. ok} boot cdrom -s
  3. Perform the fsck - You need to know the controller, target, drive, and slice of the root filesystem:
    4. # fsck -y /dev/rdsk/c0t0d0s0
  4. If the filesystem is mirrored with SVM, you should fsck both halves of the mirror:
    5. # fsck -y /dev/rdsk/c0t1d0s0
  5. If fsck reports errors, run it again until the filesystem is clean
  6. If fsck still can't fix the errors, get a list of alternate superblocks:
    7. # newfs -N /dev/rdsk/c0t0d0s0
  7. Perform the fsck using an alternate superblock - The example below uses the first alternate superblock (32):
    8. # fsck -y -F ufs -o b=32 /dev/rdsk/c0t0d0s0
  8. If it still doesn't work, you're pretty much screwed