Very often MicroBOSH runs out of storage memory. To enlarge its storage you need to attach new disk and use following script.
disk_image=/dev/xvdb
disk_part=/dev/xvdb1
part_size=38912
part_offset=63s
sudo parted --script ${disk_image} mklabel msdos
sudo parted --script ${disk_image} mkpart primary ext2 $part_offset $part_size
sudo mkfs.ext4 $disk_part
sudo mkdir -p /var/vcap/data-copy
sudo mount $disk_part /var/vcap/data-copy
sudo rsync -avzh /var/vcap/data/ /var/vcap/data-copy
sudo /var/vcap/bosh/bin/monit stop all
sudo umount /var/vcap/data-copy
sudo umount -l /var/vcap/data
sudo mount $disk_part /var/vcap/data
sudo /var/vcap/bosh/bin/monit start all