Peel potatoes, carrots, parsley and celery roots and onion.
Take medium-large pot and fill it with 2l water. Put potatoes, carrots, celery root, parsley roots into salty to it and bring it to boil.
Cook for about 40 minutes and be careful to not overcook the vegetables!
In the meantime chop onion, dice pickles and hard-boiled eggs and place it in a large mixing bowl.
Chop parsley or chives.
When the vegetables are cooked, drain them (I would recommend to keep the broth and use it differently) and let them cool down.
As soon as the vegetables are cold, dice them and put in the mixing bowl with other ingredients. Add mayo, salt, pepper and herbs and mix all well carefully.
The consistency of the salad should be smooth and creamy! When it is, try it and correct seasoning if needed.