Troubleshooting synchronization failures
The majority of synchronization problems involve the connection state of the external servers and the synchronization of the data between the two endpoints. Make sure PingDataSync can properly fail over to another endpoint or server instance if the connection fails on the highest priority external server.
Another factor in troubleshooting synchronization is determining if the distinguished name (DN) and attribute mappings were properly configured and if the information is properly being synchronized across the network. Typical scenarios include checking for any entry failures and mapping issues.
Use the |
While many PingDataSync issues are deployment-related and are directly affected by the hardware, software, and network structure used in the synchronization topology, most failures usually fall into one of the following categories:
- Entry Already Exists
-
When an add operation was attempted on the destination server, an entry with the same DN already exists.
- No Match Found
-
A match was not found at the destination based on the current Sync Classes and correlation rules (DN and attribute mapping). When this value has a high count, correlation rule problems are likely.
- Failure at Resource
-
Indicates that some other error happened during the synchronization process that does not fall into the first two categories. Typically, these errors are communication problems with a source or destination server.
Statistics for these and other types of errors are kept in the cn=monitor
branch and can be viewed directly using the status
command.
Troubleshooting "Entry Already Exists" failures
About this task
If there is a count for the EntryAlready Exists
statistic using the status
tool, verify the problem in the sync log. For example, the status
tool displays the following information:
--- Ops Completed for 'DS1 to DS2' Sync Pipe --- Op Result : Count -----------------------:------ Success : 0 Out Of Scope : 0 Op Type Not Synced : 0 No Change Needed : 0 Entry Already Exists : 1 No Match Found : 1 Multiple Matches Found : 0 Failed During Mapping : 0 Failed At Resource : 0 Unexpected Exception : 0 Total : 2
Verify the change by viewing the <server-root>/logs/sync
file to see the specific operation, which could be caused by someone manually adding the entry on the target server:
op=2 changeNumber=529277 replicationCSN=00000128AD0D9BA01E960008137D replicaID=7830 pipe="DS1 to DS2" class="DEFAULT" msg="Detected ADD of uid=user.1001,ou=People, dc=example,dc=com at ldap://server1.example.com:1389, but cannot create this entry at the destination because an equivalent entry already exists at ldap://server3. example.com:3389. Details: Search using [search-criteria dn: uid=user.1001,ou=People, dc=example,dc=com attrsToGet: [*, dn]] returned results; [uid=user.1001,ou=People, dc=example,dc=com]. "
Perform the following steps to troubleshoot this type of problem:
Steps
-
Assuming that a possible DN mapping is ill-formed, first run the
ldap-diff
utility to compare the entries on the source and destination servers. Then look at theldap-diff
results with the mapping rules to determine shy the original search did not find a match.$ bin/ldap-diff \ --outputLDIF config-difference.ldif \ --baseDN "dc=example,dc=com" \ --sourceHost server1.example.com \ --targetHost server2.example.com \ --sourcePort 1389 \ --targetPort 3389 \ --sourceBindDN "cn=Directory Manager" \ --sourceBindPassword password \ --searchFilter "(uid=1234)"
-
Review the destination server access logs to verify the search and filters used to find the entry. Typically, the key correlation attributes are not synchronized.
-
If the mapping rule attributes are not synchronized, review the Sync Classes and mapping rules, and use the information from the
ldap-diff
results to determine why a specific attribute might not be getting updated. Some questions to answer are as follows:-
Is there more than one Sync Class that the operation could match?
-
If using an
include-base-dn
orinclude-filter
in the mapping rules, does this exclude this operation by mistake? -
If using an attribute map, are the mappings correct? Usually, the cause of this error is in the destination mapping attribute settings. For example, if a set of correlation attributes is defined as:
dn
,mobile
,accountNumber
, and theaccountNumber
changes for some reason, future operations on this entry will fail. To resolve this, either removeaccountNumber
from the rule, or add a second rule as:dn,mobile
. The second rule is used only if the search using the first set of attributes fails. In this case, the entry is found and theaccountNumber
information is updated.
-
-
If deletes are being synchronized, check to see if there was a previous delete of this entry that was not synchronized properly. In some cases, simpler logic should be used for deletes because of the available attributes in the change logs. This scenario could cause an entry to not be deleted for some reason, which would cause an issue when a new entry with the same DN is added later. Use this information for mapping rules to see why the original search did not find a match.
-
Look at the destination directory server access logs to verify the search and filters it used to find the entry. Typically, the key attribute mappings are not synchronized.
Troubleshooting "No Match Found" failures
About this task
If there is a count for the No Match Found statistic using the status
tool, verify the problem in the sync log. For example, if the status
tool displays the following:
--- Ops Completed for 'DS1 to DS2' Sync Pipe --- Op Result : Count -----------------------:------ Success : 0 Out Of Scope : 0 Op Type Not Synced : 0 No Change Needed : 0 Entry Already Exists : 1 No Match Found : 1 Multiple Matches Found : 0 Failed During Mapping : 0 Failed At Resource : 0 Unexpected Exception : 0 Total : 2
Verify the change in the <server-root>/logs/sync
file to see the specific operation:
[12/May/2016:10:30:45 -0500] category=SYNC severity=MILD_WARNING msgID=1893793952 op=4159648 changeNumber=6648922 replicationCSN=4beadaf4002f21150000 replicaID=8469- ou=test,dc=example,dc=com pipe="DS1 to DS2" class="Others" msg="Detected DELETE of 'uid=1234,ou=test,dc=example,dc=com' at ldap://server1.example.com:389, but cannot DELETE this entry at the destination because no matching entries were found at ldap:// server2.example.com:389. Details: Search using [search-criteria dn: uid=1234,ou=test,dc=alu,dc=com filter: (nsUniqueId=3a324c60-5ddb11df-80ffe681- 717b93af) attrsToGet: [*, accountNumber, dn, entryuuid, mobile, nsUniqueId, object- Class]] returned no results."
Perform the following steps to fix the issue:
Steps
-
Test the search using the filter in the error message, if displayed. For example, if the sync log specifies
filter: (nsUniqueId=3a324c60-5ddb11df-80ffe681-717b93af)
, use theldapsearch
tool to test the filter. If it is successful, is there anything in the attribute mappings that would exclude this from working properly? -
Test the search using the full DN as the base. For example, use
ldapsearch
with the full DN(uid=1234,ou=People,dc=example,dc=com)
. If it is successful, does the entry contain the attribute used in the mapping rule? If the attribute is not in the entry, determine if there is a reason why this value was not synchronized. Look at the attribute mappings and the filters used in the Sync Classes.
Troubleshooting "Failed at Resource" failures
About this task
If there is a count for the "Failed at Resource" statistic using the status
tool, verify the problem in the sync log. For example, if the status
tool displays the following information:
--- Ops Completed for 'DS1 to DS2' Sync Pipe --- Op Result : Count -----------------------:------ Success : 0 Out Of Scope : 0 Op Type Not Synced : 0 No Change Needed : 0 Entry Already Exists : 0 No Match Found : 0 Multiple Matches Found : 0 Failed During Mapping : 0 Failed At Resource : 1 Unexpected Exception : 0 Total :1
This will register after a change is detected at the source in any of the following cases:
-
If the fetch of the full source entry fails. The entry exists but there is a connection failure, server down, timeout, or something similar.
-
If the fetch of the destination entry fails or if the modification to the destination fails for an exceptional reason (but not for "Entry Already Exists," "Multiple Matches Found," or "No Match Found" issues).
Verify the change by viewing the <server-root>/logs/sync
file to see the specific operation. If any of the following result codes are listed , the server is experiencing timeout errors:
-
resultCode=timeout: errorMessage=A client-side timeout was encountered while waiting 60000ms for a search response from server server1.example.com:1389
-
resultCode=timeout: errorMessage=An I/O error occurred while trying to read the response from the server
-
resultCode=server down: errorMessage=An I/O error occurred while trying to read the response from the server
-
resultCode=server down: errorMessage=The connection to server server1.example.com:1389 was closed while waiting for a response to search request SearchRequest
-
resultCode=object class violation: errorMessage='Entry device=1234,dc=example,dc=com violates the Directory Server schema configuration because it contains undefined object class
With these "Failure at Destination" timeout errors, look at the following settings in the PingDirectory server to determine if adjustments are needed:
Steps
-
For External Server Properties, check the connect-timeout property. This property specifies the maximum length of time to wait for a connection to be established before giving up and considering the server unavailable.
-
For the Sync Destination/Sync Source Properties, check the
response-timeout
property. This property specifies the maximum length of time that an operation should be allowed to be blocked while waiting for a response from the server. A value of zero indicates that there should be no client-side timeout. In this case, the server’s default will be used.$ bin/dsconfig --no-prompt --port 389 \ --bindDN "cn=Directory Manager" \ --bindPassword password list-external-servers \ --property connect-timeout
External Server : Type : connect-timeout : response- timeout ------------------------:------------------:-----------------:----------- server1.example.com:389 : sundsee-ds : 10 s : - server2.example.com:389 : sundsee-ds : 10 s : - server3.example.com:389 : ping-identity-ds : 10 s : - server4.example.com:389 : ping-identity-ds : 10 s : -
-
For Sync Pipe Properties, check the
max-operation-attempts
,retry-backoff-initialwait
,retry-backoff-max-wait
,retry-backoff-increase-by
,retry-backoff-percentage-increase
. These Sync Pipe properties provide tuning parameters that are used in conjunction with the timeout settings. When a Sync Pipe experiences an error, it will use these settings to determine how often and quickly it will retry the operation.$ bin/dsconfig --no-prompt list-sync-pipes \ --property max-operation-attempts --property retry-backoff-initial-wait \ --property retry-backoff-max-wait --property retry-backoff-increase-by \ --property retry-backoff-percentage-increase \ --port 389 --bindDN "cn=Directory Manager" \ --bindPassword password