Allow serial deployment instead of parallel
When executing a data deployment, an 'Unable to lock row' error can occur if multiple transactions try to lock the same record in Salesforce.
Because the batches are executed parallel, the chances of getting this error high, depending on the situation.
For example the master record in a master:detail relationship will always get locked when a DML is executed on the child record.
If two batches are executed at the same time and they both have at least 1 record that references the same parent, then a locking error will occur.