ISE Backup Failing 2.4

[mumbles202]

I'm trying to do a backup of an ISE server running 2.4 that was part of a cluster before but is now standalone (the 2nd server was taken offline but nothing in the configuration was actually changed).  The server appears to be functioning normally other than being a bit sluggish as of late.  Trying to do a backup and it keeps failing w/ the following:

ISE INDEXING ENGINE BACKUP FAILED : Errors in ADE.log. Backup aborted

Looking online it seems to suggest doing a "application reset-config" might resolve it.  I'm not familiar with the command but wanted to know what else I can look at in terms of getting the backups working again.  Also, what would be the correct way to remove the reference to the now defunct server?

[davidgfriedman · Accepted solution]

Do not run application reset-config, that will erase your box and all policies, conditions, NADs, etc. Try ssh'ing into the unit to view the last 100 lines of the ADE.log with the below command. It should give you something to follow to resolve your backup failure:
show logging system ade/ADE.log tail count 100

[Arne Bier · Accepted solution]

Are you able to make this Standby server a Primary?  I would try promoting it to a Primary, and then seeing if you can do the backup. And also, see if you can de-register the defunct node. If the backup works, then you could restore that on a fresh 2.4 (or 2.7) node and that should strip out any reference to other previously registered nodes in the deployment - in other words, you will restore all the config onto a single node.