- Prerequisites for Aging/Scavenging
- Aging/Scavenging Terminology
- When Scavenging Can Start
- Example of the Aging/Scavenging Process for a Sample Record
Aging/Scavenging Terminology
The aging and scavenging process is a new feature in Windows 2000 Server. The following table indicates new or revised terms that have been introduced to help specifically when discussing these features.
Table 1
Aging/Scavenging Terminology
Term |
Description |
Resource record (RR) time stamp |
A date and time value used by the DNS server to determine the removal of the resource record when it performs aging and scavenging operations. |
Current server time |
The current date and time on the DNS server. This number can be expressed as an exact numeric value at any point in time. |
No-refresh interval |
An interval of time, determined for each zone, as bounded by the following two events:
This value is needed to decrease the number of write operations to the Active Directory database. By default, this interval is set to 7 days. It should not be increased to an unreasonably high level because the benefits of the aging and scavenging feature might either be lost or diminished. |
Refresh interval |
An interval of time, determined for each zone, as bounded by the following two distinct events:
This value should be large enough to allow all clients to refresh their records. By default, this interval is set to 7 days. It should not be increased to an unreasonably high level, because the benefits of the aging and scavenging feature might either be lost or diminished. |
Start scavenging time |
A specific time, expressed as a number. The server uses this time to determine when a zone becomes available for scavenging. For more information, see the next section, "When Scavenging Can Start." |
Scavenging period |
When automatic scavenging is enabled at the server, this period represents the time between repetitions of the automated scavenging process. The default value for this is seven days. To prevent deterioration of DNS server performance, the minimum allowed value for this is one hour. |
Record refresh |
When a DNS dynamic update is processed for a resource record when only the resource record time stamp, and no other characteristics of the record, are revised. Refreshes generally occur for the following reasons:
|
Record update |
When a DNS dynamic update is processed for a resource record where other characteristics of the record in addition to its time stamp are revised. Updates generally occur for the following reasons:
|
Scavenging servers |
An optional advanced zone parameter that enables you to specify a restricted list of IP addresses for DNS servers that are enabled to perform scavenging of the zone. By default, if this parameter is not specified, all Windows 2000 DNS servers enabled to use scavenging that load a directory-integrated zone (also enabled for scavenging) attempt to perform scavenging of the zone. In some cases, this parameter can be useful if it is preferable that scavenging only be performed at some servers loading the directory-integrated zone. To set this parameter, you must specify the list of IP addresses for the servers enabled to scavenge the zone in the ScavengingServers parameter for the zone. This can be done using the dnscmd command, a command-line based tool for administering Windows DNS servers. |