Backup fails when attachments (1.9 GB) stored in external (MySQL) database

Dear all,

1.
we have 1.9 GB attachment data.
After migration of the attachments from the filesystem approach to the recommended database approach no backup is running any more: we get allways Java heap space errors. When using filesystem as storage location backup is successful.
The database approach is recommended by Atlassian and it is necessary for cluster architecure and upgrade to another master release version.

2.
when once switched to database storage approach of attachments no switch back to filesystem storage (1.9 GB data)

Chears,

Stefan