document what to do *after* migration

[mhow2]

Hi,
I've successfully applied the migration to WiredTiger, however we are left with a transitional docker-compose.yml. Maybe a good thing would be to document what to do with this file after the migration. Things I'm thinking:

• remove the dependency to the migrator service
• cleanup the local folder (remove docker folder).
• what do to with the while loop in mongo service waiting for WiredTiger migration ?

[mhow2]

@frdmn what do you think ?

[lwsystems]

After finnishing migration, I've changed the old compose file in the following way.
Set mongo version to 4.2 and start the mongo process with
command: mongod --oplogSize 128 --replSet rs0 --storageEngine=wiredTiger
After upgrade, images seemed to be loaded very slow. But I've no idea if this is an mongo issue.

[ChetanGoti]

@lwsystems I faced the same issue after I migrated to wiredTiger engine. (I'm using GridFS)

It seems the index is missing on the attachments. Creating an index as mentioned at RocketChat/Rocket.Chat#24266 (comment) fixed the issue.