Mi modelo:

class Course(models.Model):
    language = models.ForeignKey(Language)
    name = models.CharField(max_length=50, unique=True, default='course')
    title = models.CharField(max_length=1024, default='no title')
    foreign_title = models.CharField(max_length=1024, default='no title', blank=True)
    header = models.CharField(max_length=1024, default='', blank=True)
    description = models.TextField(null=True, blank=True)

    def __str__(self):
        return self.title

    def __unicode__(self):
        return u'%s' % self.title

Estoy agregando "unique_together":

class Course(models.Model):
    language = models.ForeignKey(Language)
    name = models.CharField(max_length=50, unique=True, default='course')
    title = models.CharField(max_length=1024, default='no title')
    foreign_title = models.CharField(max_length=1024, default='no title', blank=True)
    header = models.CharField(max_length=1024, default='', blank=True)
    description = models.TextField(null=True, blank=True)

    class Meta:
        unique_together = ['language', 'name', 'title']

    def __str__(self):
        return self.title

    def __unicode__(self):
        return u'%s' % self.title

Tiempo en la migración obteniendo el error:

 django.db.utils.OperationalError: (1071, 'Specified key was too long; max key length is 767 bytes')

Mi base de datos es: mysql Ver 15.1 Distrib 10.0.17-MariaDB, para debian-linux-gnu (x86_64) usando readline 5.2

Traté de aumentar la longitud del índice mysql:

MariaDB [(none)]> set global innodb_file_format = BARRACUDA;
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> set global innodb_large_prefix = ON;
Query OK, 0 rows affected (0.00 sec)

Pero esto todavía no es suficiente:

django.db.utils.OperationalError: (1071, 'Specified key was too long; max key length is 3072 bytes')

La longitud del índice del problema. ¿Cómo especificar el límite de longitud del índice Django?