One DC or two DCs for an SMB office?
Two is almost always the right answer; one DC is a single point of failure for logon, DNS and GPOs.
support/servers-on-premise/ad-een-of-twee-domain-controllerssteps: 4
Try this first
- Two DCs, ideally separate hosts or sites
- Both run DNS, verify replication
- Split or consciously keep FSMO roles together
- System-state backup on both
When to bring us in
Growing to multiple offices: configure AD Sites and Services properly for replication traffic.
See also
- Should I split FSMO roles across two DCs?For a small domain all on one DC is fine; with two DCs splitting is tidier but not required.
- How do I know my AD replication is healthy?Replication errors creep in silently; they only surface when logins or GPOs misbehave.
- Logins are slow at the second office.Subnets are often missing in Sites and Services so clients hit a DC over the WAN.
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