We are considering moving from Dell to Supermicro servers. The main concern from management is what to do with maintenance. What do you guys do for same day onsite service maintenance plans?
Have your own collection of spare parts, tools, and people who know how to use them. Relying on any third party for time-critical support is a fast road to stress, pain, and suffering.
You may think that you have an agreement with a service provider, but I can guarantee you that it is neither as iron-clad as you might think, nor does it have sufficient compensation to cover the loss of goodwill you will suffer, and your own costs in crediting SLAs with your own customers.
My former employer, who does this particular aspect of their business very well, has formerly been a Supermicro customer, and is now a Dell customer. In both cases, they kept their own complete stock of spares, including all the necessary parts as well as entire chassis. They have never had cause to regret this plan.
If you worry that this is an undue cost, consider that you can offset the costs of your local stockpile by getting rid of the gold-plated 4-hour onsite warranty with added vitamins and minerals, and just go with a lower grade support contract.