An Illustrated Guide to Exclusions and Preservers in Instance CloningSummary<!-- /*NS Branding Styles*/ --> .ns-kb-css-body-editor-container { p { font-size: 12pt; font-family: Lato; color: var(--now-color--text-primary, #000000); } span { font-size: 12pt; font-family: Lato; color: var(--now-color--text-primary, #000000); } h2 { font-size: 24pt; font-family: Lato; color: var(--now-color--text-primary, black); } h3 { font-size: 18pt; font-family: Lato; color: var(--now-color--text-primary, black); } h4 { font-size: 14pt; font-family: Lato; color: var(--now-color--text-primary, black); } a { font-size: 12pt; font-family: Lato; color: var(--now-color--link-primary, #00718F); } a:hover { font-size: 12pt; color: var(--now-color--link-primary, #024F69); } a:target { font-size: 12pt; color: var(--now-color--link-primary, #032D42); } a:visited { font-size: 12pt; color: var(--now-color--link-primary, #00718f); } ul { font-size: 12pt; font-family: Lato; } li { font-size: 12pt; font-family: Lato; } img { display: ; max-width: ; width: ; height: ; } } The ServiceNow Platform allows a wide variety of configuration in the area of cloning to allow instance administrators to thus obtain the specific results needed in the resultant target at completion of the clone. However, due to the many option choices, it can sometimes be confusing as to what the final result of a clone might be, in particular with regards to the application of Clone Data Preservers and Clone Table Exclusions. This Knowledge Base article will attempt to clear up some of that confusion with a series of diagrams and descriptions of what the final result would be for the various options of Exclusion (Exclude Tables) and Preservation (Preserve Data) for that table. To begin, say we have two instances, "Source" and "Target" and we intend to thus perform a Clone Request from instance "Source" over instance "Target". Both of these instances thus have a table with the name "Automobile". Some records in this table are found on both instances, while other such records are found on one or the other of these instances. The following diagram would thus show how this table might appear before any Cloning were to occur. We will next perform several example clones, using different combinations of Clone Data Exclusions and Data Preservers on this "Automobile" table to visualize the final state of these tables upon completion of the clone. For our first example clone, say that we have neither a Clone Data Preserver nor a Data Exclusion record configured for use during the Clone request on this table. The following would thus be the final state of the Automobile table, as found on the target instance: As will be noticed in this Clone configuration, the final state of the Automobile table on the target instance will thus contain all records from the source but none from the target. Since there was no Exclusion thus used during the clone operation all records from the target instance table. However, since no records were configured to be preserved, no records from the target were thus retained on the cloned instance. The next example clone will be performed with both a table Exclusion set AND a table Preserver set for the "Automobile" table. As will be seen, with this specific combination of Clone Preserver and Clone Exclusion, the final state of the target instance will contain all records as found on the target instance from before the clone was run and none of the records from the source instance's table. The Clone had been configured to Exclude this table, nothing was copied from the source and since the table was included with the Clone Data Preservers for this Clone Request, all records from the target were found on the target instance upon final completion of the Clone oepration. The next example will show the results of a Clone Request in which a Clone Preserver was configured, but not a Clone Exclusion record on this table. The final result of the "Automobile" table upon completion of this Clone Request is a sort of hybrid of both instances. First, because no Exclusion was included from this table, ALL records from the source table were copied to the target instance. However, since a Clone Data Preserver for that same table was also included in the Clone Request, all tables from the target were then overwritten to the target instance. Thus, for any records that were only found on the source instance, these records would be found on the target in the same state as from the source. For any records that were only found on the target instance (before the Clone was performed), the record will be retained on the target in the same status as on the target instance. For any records that were found on both the source and target (as recognized by the unique key, which is usually the sys_id field), the target version of the record will thus overwrite the version of the record as copied from the source. Lastly we have the case in which an Exclusion is configured for the record but no Preserver is configured for the "Automobile" table. In this particular configuration, it will be noted that, while the table structure of the "Automobiles" table is copied from the source to the target, the table contains no actual data. Since no records were preserved on the target and all records were excluded from the source the table will therefore be found to be completely empty.