http://adirectory.blog.com/2013/03/raise-domain-functional-level-directory-service-busy/
提升林功能级别的时候提示目录繁忙。 环境是2台win srv 2003的环境的DC，在提示林功能级别的时候提示目录繁忙。域的复制存在问题，ntds replication 2023这个错误，除了上面提示的RPC服务不可用（事实上rpc服务都是起来的），还发现一个问题，主域控server2 无法ping通额外域控dcback（防火墙是关闭的），但是dcback可以ping通server2，
netdiag和dcdiag的信息如下：
….
DNS test . . . . . . . . . . . . . : Failed
[WARNING] Cannot find a primary authoritative DNS server for the name
‘server2.cen.com.cn.’. [ERROR_TIMEOUT]
The name ‘server2.cen.com.cn.’ may not be registered in DNS.
[WARNING] The DNS entries for this DC are not registered correctly on DNS server ’192.168.32.8′. Please wait for 30 minutes for DNS server replication.
[FATAL] No DNS servers have the DNS records for this DC registered.
Doing primary tests
Testing server: Default-First-Site-Name\SERVER2
Starting test: Replications
[Replications Check,SERVER2] A recent replication attempt failed:
From DCBACK to SERVER2
Naming Context: DC=ForestDnsZones,DC=cen,DC=com,DC=cn
The replication generated an error (1256):
远程系统不可用。有关网络疑难解答，请参阅 Windows 帮助。
The failure occurred at 2011-01-11 14:37:44.
The last success occurred at 2010-05-31 13:15:41.
21548 failures have occurred since the last success.
[DCBACK] DsBindWithSpnEx() failed with error 1722,
RPC 服务器不可用。.
[Replications Check,SERVER2] A recent replication attempt failed:
From DCBACK to SERVER2
Naming Context: DC=DomainDnsZones,DC=cen,DC=com,DC=cn
The replication generated an error (1256):
远程系统不可用。有关网络疑难解答，请参阅 Windows 帮助。
The failure occurred at 2011-01-11 14:37:44.
The last success occurred at 2010-05-31 13:15:41.
21559 failures have occurred since the last success.
[Replications Check,SERVER2] A recent replication attempt failed:
From DCBACK to SERVER2
Naming Context: CN=Schema,CN=Configuration,DC=cen,DC=com,DC=cn
The replication generated an error (1722):
RPC 服务器不可用。
The failure occurred at 2011-01-11 14:38:26.
The last success occurred at 2010-05-31 13:15:41.
21548 failures have occurred since the last success.
The source remains down. Please check the machine.
[Replications Check,SERVER2] A recent replication attempt failed:
From DCBACK to SERVER2
Naming Context: CN=Configuration,DC=cen,DC=com,DC=cn
The replication generated an error (1722):
RPC 服务器不可用。
The failure occurred at 2011-01-11 14:38:05.
The last success occurred at 2010-05-31 13:21:22.
21548 failures have occurred since the last success.
The source remains down. Please check the machine.
[Replications Check,SERVER2] A recent replication attempt failed:
From DCBACK to SERVER2
Naming Context: DC=cen,DC=com,DC=cn
The replication generated an error (1722):
RPC 服务器不可用。
The failure occurred at 2011-01-11 14:37:44.
The last success occurred at 2010-05-31 13:21:33.
21548 failures have occurred since the last success.
The source remains down. Please check the machine.
REPLICATION-RECEIVED LATENCY WARNING
SERVER2: Current time is 2011-01-11 14:47:29.
DC=ForestDnsZones,DC=cen,DC=com,DC=cn
Last replication recieved from DCBACK at 2010-05-31 13:15:41.
WARNING: This latency is over the Tombstone Lifetime of 60 days!
DC=DomainDnsZones,DC=cen,DC=com,DC=cn
Last replication recieved from DCBACK at 2010-05-31 13:15:41.
WARNING: This latency is over the Tombstone Lifetime of 60 days!
CN=Schema,CN=Configuration,DC=cen,DC=com,DC=cn
Last replication recieved from DCBACK at 2010-05-31 13:15:41.
WARNING: This latency is over the Tombstone Lifetime of 60 days!
CN=Configuration,DC=cen,DC=com,DC=cn
Last replication recieved from DCBACK at 2010-05-31 13:21:22.
WARNING: This latency is over the Tombstone Lifetime of 60 days!
DC=cen,DC=com,DC=cn
Last replication recieved from DCBACK at 2010-05-31 13:21:34.
WARNING: This latency is over the Tombstone Lifetime of 60 days!
…
回答： 根据您的描述，我对这个问题的理解是您在提升域的森林功能级别是提示错误. 您看到的文章来自活动目录seo http://adirectory.blog.com/category/active-directory/
在我们进行之前，让我们共同看下下面的问题：
如果Server2不能Ping同dcback，那么通过\\dcback的方法可以从server2访问到dcback的共享么？
如果在您执行一次失败后，那么您再次执行升级森林级别，是不是有同样的错误？
您可以正常的执行升级域的功能级别么？
从我的经验看，出现“目录繁忙“的状况在大部分的情况下是由于DC之间相互复制时，没有相应的资源去运行升级操作，才会导致这样的问题，所以等一段时间等复制全部完成，再执行时看是否会有这样的问题。
如果等一段时间，再次运行升级操作时如果提示同样的错误，那么我们可以从下面的几个问题分析：
由于双宿主机在Domain环境中很可能会引起域名解析方面的问题，所以通过下面的方法去停止第二块网卡：
1) 右键单击网上邻居> 点击属性> 在新的窗口中，右键单击没有使用的块网卡，并单击属性。
2) 双击internet 协议 (TCP/IP)，点击高级，在新窗口中点击DNS标签> 确保“在DNS中注册此链接的地址”选项没有被选中。
3) 点击确定，同时禁用此网卡。
在网卡禁用后，运行下面的命令：
Ipconfig /flushdns
Ipconfig /registerdns
Net stop netlogon && net start netlogon
确保Server2和dcback的防火墙都是被关闭的，我们可以用portqry去查询：
您可以访问下面的完整，获取portqry工具：
http://support.microsoft.com/kb/832919/zh-cn
单击“开始”，单击“运行”，在“打开”框中键入“cmd”，然后单击“确定”。
键入portqry -n problem_server -e 135
键入portqry -n problem_server -o 1094,1025,1029,6004
确保这些端口都是出于LISTENING
张方方 微软全球技术支持中心