Why macOS Server is Slow and How to Improve Its Performance

Apple’s commitment to the provision of advanced server tools to its customers is waning by the day. The company has recently issued a statement notifying its users of the upcoming changes in how its macOS Server works. Specifically, in the spring release of the app, numerous services and tools such as Calendar, DHCP, DNS, NetInstall, and Mail will be deprecated. However, taking into consideration the fact that macOS Server is geared toward macOS and iOS devices, many system administrators do not consider alternative servers. After all, there is no a better solution for administrators overseeing business networks full of Apple devices.

Regretfully, some users report the unsatisfactory performance of macOS Server. The issue persists even if the app is installed on a dedicated machine that is not otherwise used. The article has been written to help system administrators improve the performance of their servers.

Where to Start

If a user has noticed the slow performance of their server, they should monitor the CPU usage of their Mac. To check the aggregate usage of CPU cores, do the following:

  1. Go to the Applications folder and open the Utilities;
  2. Locate and launch the Activity Monitor;
  3. Select the CPU tab;
  4. In the tab, check the cores and their respective loads.
mac cpu usage
Source: support.apple.com

If the Activity Monitor shows a small percentage of CPU usage, but the server is still slow, it means that the cause of the problem resides somewhere else. Open the Memory tab and check the availability of memory resources.

memory usage on mac
Source: support.apple.com

When the memory resources of the Mac are depleted, the server can become slow. If, however, the Memory Pressure graph shows that there are available memory resources, it is necessary to check the DNS server settings.

DNS Server Settings

Having proper DNS server configurations is critical for the performance of the server. Even trivial functions such as file sharing depend on DNS settings. Therefore, to improve the performance of the macOS Server, it is necessary to satisfy the following basic requirements: a fixed IP address and a properly configured DNS server.

Start by enabling DNS services. When the services are disabled, the server will substantially slow down when resolving a hostname-IP address issue.

If the network has only one server, it should run DNS for itself and network clients. The server’s IP address should be entered in the DNS server’s field. It also has to be added to the router’s DHCP service. Note that the .local suffix shouldn’t be used for the server’s hostname because it reserved for zeroconf broadcast networking. Furthermore, it is necessary to designate a DNS server as a forwarder. Without DNS forwarding external queries will be handled by all DNS servers, which increases bandwidth usage and decreases the performance of macOS Server. In addition, the internal domains will be exposed to the Web, thereby creating a security risk. It is recommended to use Google’s DNS serves for external addresses because they are the most reliable.

To change, add, or adjust forwarding settings, do the following:

  1. Open the Server app;
  2. Go to the Advanced section;
  3. Click on the cog icon;
  4. Click on the Show All Records button;
  5. Use the Edit button to enter a forwarder;
  6. Use the + button to enter an IP address for a forwarder;
  7. Click the OK