Backup Targets and Rebuilt Domain Controllers

Cygna Forest Recovery judges your backups against what a recovery needs, not against every domain controller. This topic explains how it decides which domain controllers need a backup, and how that shows on the Dashboard, the inventory screens, the command line, and the Protection Summary.

What a recovery needs

A domain recovery restores one writable domain controller from backup and rebuilds the other domain controllers of the domain by promotion. A forest recovery does the same in every domain. So you back up at least two writable domain controllers per domain, not every domain controller. The second backup is the one you fall back on if the first is unusable.

For which domain controllers to choose, see Choosing Which Domain Controllers to Back Up.

Backup targets

A domain controller with an enabled backup policy is a backup target. Every protection finding about a missing backup is about a backup target. A domain controller with no enabled policy and nothing in the vault is not a backup target: a recovery rebuilds it, so its verdict is Rebuilt on recovery. That is information, not a finding, and it raises no alert.

A disabled policy counts as no policy. A domain controller whose only policy is disabled is rebuilt on recovery when nothing of it is in the vault. When it still has a restorable backup, it reads No schedule instead, a warning, because that restore point only grows older.

Protection	Severity	When
Protected	Good	A restorable backup exists within twice the policy interval, and the last attempt succeeded.
Last backup failed	Warning	A fresh restorable backup exists, but the most recent attempt failed.
Backup stale	Warning	The newest restorable backup is older than twice the policy interval.
No schedule	Warning	A restorable backup exists, and no enabled policy will replace it.
Unprotected	Warning	A backup target with nothing restorable: the first backup has not completed, every backup failed, or every version was pruned. Raises Backup targets with nothing to restore from.
Rebuilt on recovery	Information	No enabled policy and nothing in the vault. A recovery rebuilds it by promotion. Raises no alert.

No domain controller verdict is critical. Whether losing a backup target costs its domain its recovery is a question for the domain, below.

Whether the domain can be recovered

The domain's coverage verdict on the Domains screen decides whether a domain can be recovered, whatever its rebuilt domain controllers read. A domain with two protected writable domain controllers and 198 that are rebuilt on recovery is Covered. If its backup targets lapse so that no writable domain controller holds a restorable backup, the domain turns Unrecoverable, which is critical and raises Domains that could not be recovered. Forests roll up their domains in the same way.

For every domain and forest verdict, see Coverage and Readiness.

Domain controllers that need an agent without a backup

A recovery of one domain also reconciles every global catalog outside that domain, through each global catalog's DC agent. The plan does not start while one of them has no agent. So a global catalog needs the DC agent, even if you do not back it up, when its forest holds another domain this installation would recover: a domain that still has a domain controller in the directory and is not excluded.

The Manager flags those domain controllers on each row of the domain controller inventory, and the console and the alert read the same flag:

The alert Global catalogs with no agent names only these global catalogs.
On the Domain Controllers screen, No agent is a warning on these global catalogs and on backup targets. On any other domain controller it is information, because a recovery rebuilds it and needs nothing of it. Hover over No agent to see which case applies.

A domain controller whose global catalog flag has not been read yet is not treated as a global catalog.

Sites

A site's verdict is a roll-up of its backup targets. Domain controllers rebuilt on recovery are counted and shown, but they are not findings, and no site verdict is critical: a location comes back by promotion, and the domain verdict answers whether each domain could be recovered.

Rebuilt on recovery—The site has domain controllers and none of them is a backup target. Information.
Nothing to restore—The site has backup targets, and no domain controller in it holds a restorable backup. Warning.
Partly protected—Some backup targets in the site have nothing to restore from. Warning.
Protected—Every backup target in the site is protected.

For every site verdict, see Sites.

The health chip

The health chip in the top bar rolls up the domain verdicts as well as the domain controllers' verdicts. A domain that could not be recovered turns it to Action required, and selecting the chip then opens the Domains screen. Domain controllers rebuilt on recovery do not count toward the chip. See Using the Console.

How the counts read

Protected domain controllers are counted against the backup targets. Domain controllers rebuilt on recovery are named beside them, not counted as a shortfall, with one exception. A recovery needs restorable backups of two writable domain controllers in each domain, or of every writable one in a domain that has fewer. A domain with fewer backup targets than that needs the difference, and that many of its rebuilt domain controllers stay in the figure as need a backup policy. A forest of two domains with three writable domain controllers each and no backup policy yet reads 0 of 4 · 4 need a backup policy · 2 rebuilt on recovery, not 0 of 0.

Which domain controllers take the policy is your choice, so no domain controller's own verdict changes. Read-only domain controllers neither count toward the need nor fill it. A backup target that you excluded still fills its domain's need, and an excluded domain needs nothing.

The counts read like this:

Dashboard—Each forest card's Controllers protected reads, for example, 2 of 2 with 198 rebuilt on recovery below it. See Dashboard.
Inventory screens—The Controllers column on the Forests, Domains, and Sites screens reads, for example, 2 protected · 198 rebuilt on recovery. The Domain Controllers screen has a rebuilt on recovery filter chip, and a rebuilt domain controller's Restorable backup and Schedule cells are plain text rather than warnings. See Domain Controllers.
Command line—cdr domain list, cdr forest list, and cdr site list show PROTECTED as, for example, 2/2 (198 rebuilt on recovery). A site with no backup target reads no backup targets. A domain with too few backup targets reads, for example, 0/2 (2 need a backup policy, 1 rebuilt on recovery). cdr dc list --protection rebuild lists the domain controllers that are rebuilt on recovery. See Inventory Commands.
Protection Summary—The domain table shows the numbers that need a backup policy and are rebuilt on recovery under Protected, the forest table names them beside DCs protected, and the CSV export has a column for each. See Protection Summary.

Exclusions

Exclusions are for objects that are out of scope, such as a forest reached across a trust that this installation is not meant to protect. You do not need to exclude a domain controller that recovery rebuilds: it already raises no alert, and it stays in the counts as rebuilt on recovery. An excluded domain controller leaves the counts altogether. See Excluding and Retiring Objects.

When a domain controller stops being a backup target, or a recovery no longer needs an agent on it, alert email drops it from the alert without reporting it as cleared. See Alerts Reference.