You can't change which column is default, You need to make a new one, move contents out then rename (at least last time I researched)

The default column can not be changed as far as I can tell.

You’d need to rename ‘backlog’ to ‘Needs Triage’ and move tasks as required.

However, this problem here is the large number of tasks which would create a ton of notifications.

Generally, don't worry about that. If people don't care about column moves, and haven't turned it off in their preferences... that's mostly on them :)

Or we can do the mass move for you silently. When doing a bulk job there's a interstitial that says something like "to run this job without notification, run this command on the phab server <blah blah>".

Let us know what that command is (the job number) and we'll run that command to silence it, and then you can press "do it" and, voila, no spam.

@Reedy thanks, good to know! The column move would probably be fine, but maybe it's safer to do the silent move.

@greg Sorry if this is an obvious question, but how do I figure out the job number?

You need to be in the triage group and use bulk edit, but I just checked and there isn't any workboard move options.

In T245308#5886156, @LGoto wrote:

@greg Sorry if this is an obvious question, but how do I figure out the job number?

It doesn't look like this is possible for a column move on batch edit?

vs

In T245308#5886156, @LGoto wrote:

@greg Sorry if this is an obvious question, but how do I figure out the job number?

You find the job number when doing a bulk edit eg https://phabricator.wikimedia.org/maniphest/bulk/query/.BZ.4tTLOMu1/?board=487

Unfortunately, and I'm sorry about this, the bulk editor doesn't have the option of moving tasks to a different column.

That functionality is on the workboard itself:

So doing it there with the notifications, is sadly the best path.

I'm sorry I promised something we didn't have; this use case always bites me.

In T245308#5886169, @greg wrote:

I'm sorry I promised something we didn't have; this use case always bites me.

Googling looks like this solution was the implemented solution for bulk changes like this... Is there any benefit to whinge at Phabricator (Upstream) and see if they'll add it to the jobs too?

No worries, thanks everyone for looking into this. I'll give the team a heads up and then move the tasks via the workboard.

I was about to look into this while wondering if this could simply be solved by renaming columns, but seems that @LGoto already did the right thing by renaming Needs Triage to Backlog, creating a new Needs Triage column, and moving a good bunch of tasks from Needs Triage to Backlog?

Looks like only 90 tasks moved when I first did this, though. I'm trying the "move to column" again for the remaining tasks.

Yea, FWIW, I've found Move to Column does not work consistently, and generally advise against using it when at all possible. Sorry I'm late to that suggestion. :-/