"Error Code:440878 Indexing Service too busy" when attempting a collection from Enterprise vault

Problem

An eDiscovery Collection Task fails during the search phase of the collection process.

Error Message

From the <Esa_Home>\logs\cip-logs\ICP-remoteicpjob@4702#.log

Error Code:440878 Indexing Service too busy

Captured through Dtrace on the Enterprise Vault Indexing Server:

(EVIndexVolumesProcessor) <Status Checker Thread for 1860DBBA3314F914C901CEA92E1E671941110000EVSITE.CWLAB.COM_15559:3380> EV-M 
{STATUSCHECKER.EN_US} No Additions acknowledgements received for a while, waiting for 123 pending items. Number of unfruitful attempts 30.
Indexing engine is probably too busy. Will STOP for now.

Cause

1. The Enterprise Vault Store Database table Saveset requires an additional index (affects EV10.0.2 - 10.0.4)

2. The Enterprise Vault server does not have the resources needed to complete the search and retrieval requests.

Solution

Cause 1 Resolution: 
EV10.0.2 - 10.0.4 environments

• From the SQL server, open each EV Vault Store database and expand the tables | Saveset | Indexes
• Determine if the index is present:  IX_Saveset_idPartition_ArchivePointIdentity or Saveset_IdPartition_ArchivePointIdentity

If the index is not present, please contact Enterprise Vault Technical support for assistance in creating the additional index.
REF: 000020076

Cause 2 Resolution:
This list of recommended parameters are resolutions to the most common causes of resource issues.

1. Vault Service Account (VSA) temp folder needs a minimum of 20GB of free space.
2. Exclude the VSA temp folder from Anti-Virus scanning.
3. Add additional paging files.
4. Add additional RAM to Enterprise Vault server.
5. Disable monitoring software on the Enterprise Vault server.