CODEWITHSUNDEEP
mongodb
giorgiosironi
giorgiosironi

Reputation: 1104

MongoDB initial sync very slow

We're syncing a new server to our MMAPv1 replica set, and since this one uses the wiredTiger storage engine, we have to do an initial sync.

Right now the process is inserting only several thousands documents per hour. Is there a way to debug what is the bottleneck?

Both CPU and IO seem not to be a problem, this is a sample iostat:

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.99    0.05    0.52    4.01    1.00   92.43

The new server is syncing from a secondary, which has similar metrics.

Upvotes: 4

Views: 924

Answers (1)

giorgiosironi
giorgiosironi

Reputation: 1104

We had fastsync=true inside the configuration file. With this setting the server only replicated new data, not existing data.

Upvotes: 2

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