diff --git a/core/admin/mailu/models.py b/core/admin/mailu/models.py
index 15685abd..27165e8e 100644
--- a/core/admin/mailu/models.py
+++ b/core/admin/mailu/models.py
@@ -131,7 +131,7 @@ class Domain(Base):
         backref=db.backref('manager_of'), lazy='dynamic')
     max_users = db.Column(db.Integer, nullable=False, default=-1)
     max_aliases = db.Column(db.Integer, nullable=False, default=-1)
-    max_quota_bytes = db.Column(db.Integer(), nullable=False, default=0)
+    max_quota_bytes = db.Column(db.BigInteger(), nullable=False, default=0)
     signup_enabled = db.Column(db.Boolean(), nullable=False, default=False)
 
     @property
@@ -307,8 +307,8 @@ class User(Base, Email):
     domain = db.relationship(Domain,
         backref=db.backref('users', cascade='all, delete-orphan'))
     password = db.Column(db.String(255), nullable=False)
-    quota_bytes = db.Column(db.Integer(), nullable=False, default=10**9)
-    quota_bytes_used = db.Column(db.Integer(), nullable=False, default=0)
+    quota_bytes = db.Column(db.BigInteger(), nullable=False, default=10**9)
+    quota_bytes_used = db.Column(db.BigInteger(), nullable=False, default=0)
     global_admin = db.Column(db.Boolean(), nullable=False, default=False)
     enabled = db.Column(db.Boolean(), nullable=False, default=True)
 
diff --git a/core/admin/migrations/versions/3b7eee912b41_.py b/core/admin/migrations/versions/3b7eee912b41_.py
new file mode 100644
index 00000000..17f1e0ef
--- /dev/null
+++ b/core/admin/migrations/versions/3b7eee912b41_.py
@@ -0,0 +1,30 @@
+"""change quota type to bigint
+
+Revision ID: 3b7eee912b41
+Revises: fc099bd15cbe
+Create Date: 2019-01-15 08:51:05.346257
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '3b7eee912b41'
+down_revision = 'fc099bd15cbe'
+
+from alembic import op
+import sqlalchemy as sa
+
+def upgrade():
+    with op.batch_alter_table('domain') as batch:
+        batch.alter_column('max_quota_bytes', type_=sa.BigInteger(), nullable=False, server_default='0')
+
+    with op.batch_alter_table('user') as batch:
+        batch.alter_column('quota_bytes', type_=sa.BigInteger(), nullable=False)
+        batch.alter_column('quota_bytes_used', type_=sa.BigInteger(), nullable=False, server_default='0')
+
+def downgrade():
+    with op.batch_alter_table('domain') as batch:
+        batch.alter_column('max_quota_bytes', type_=sa.Integer(), nullable=False, server_default='0')
+
+    with op.batch_alter_table('user') as batch:
+        batch.alter_column('quota_bytes', type_=sa.Integer(), nullable=False)
+        batch.alter_column('quota_bytes_used', type_=sa.Integer(), nullable=False, server_default='0')