PSA unable to write when S is stopped

[John_Torr]

Hi,

I have checked docs and done many searches on this topic and thought I had it all figured but it just still doesn’t work out.

I have 16 shards in my cluster each is a PSA

I have set the default Write Concern to 1

db.adminCommand({
    "setDefaultRWConcern" : 1,
    "defaultWriteConcern" : {
        "w" : 1
    },
    "defaultReadConcern" : {
        "level" : "available"
    }
})

I am insert_many with Python drivers and making sure to set the WriteConcern to 0 as with bulk operations.

curs = db_col.with_options(write_concern=WriteConcern(w=0)).insert_many(data)

Yet still when I shut down an S member of any shard the whole insert stops working until I bring the S back up again.

Any idea what else I can do?

[Kobe_W]

@John_Torr

the whole insert stops working

what you mean by this?
timeout? exception? blocking forever?

[Ramachandra_Tummala]

Majority data bearing nodes should be up to acknowledge writes but Arbiter is a non data bearing
Check this link

Best practices ReplicaSet MongoDB

Good day, colleagues! We use a highly loaded MongoDB database in a ReplicaSet configuration, which includes one primary node, 3 secondary nodes and one arbiter. One of the secondary nodes became in the recovering state, and at the same time, one of the secondary nodes was stopped. Multiple “slow query” type errors were recorded. We are using version 4.4.3. Tell me what configuration we should use to avoid such problems and maybe there are some best practices for configuring the database.

[John_Torr]

I probably should have mentioned it is MongoDB 6.0.4
So it is supposed to work when Write Concern w=1 even with only PA up and S down, Isn’t it?

From the client the queries just stop and sit there not doing anything until S is back up again.

Here is a snippet from the current_ops which looks interesting

'numYields': 0,
   'waitingForLatch': {'timestamp': '2023-05-03T08:00:09.812+00:00',
    'captureName': 'FlowControlTicketHolder::_mutex'},
   'locks': {},
   'waitingForLock': False,
   'lockStats': {},
   'waitingForFlowControl': True,
   'flowControlStats': {'acquireWaitCount': 1,