mongodb/jstests/mmap_v1/use_power_of_2_a.js

// test the newCollectionsUsePowerOf2Sizes param
function test(defaultMode) {
    // default should be server default
    db.a.drop();
    db.createCollection('a');
    assert.eq(db.a.stats().userFlags & 1, defaultMode);

    // explicitly turned off should be 0
    db.b.drop();
    db.createCollection('b', {usePowerOf2Sizes: false});
    assert.eq(db.b.stats().userFlags & 1, 0);

    // Capped collections now behave like regular collections in terms of userFlags. Previously they
    // were always 0, unless collmod was used.

    // capped should obey default (even though it is ignored)
    db.c.drop();
    db.createCollection('c', {capped: true, size: 10});
    assert.eq(db.c.stats().userFlags & 1, defaultMode);

    // capped explicitly off should be 0
    db.d.drop();
    db.createCollection('d', {capped: true, size: 10, usePowerOf2Sizes: false});
    assert.eq(db.d.stats().userFlags & 1, 0);

    // capped and ask explicitly for powerOf2 should be 1
    db.e.drop();
    db.createCollection('e', {capped: true, size: 10, usePowerOf2Sizes: true});
    assert.eq(db.e.stats().userFlags & 1, 1);
}

assert.eq(db.adminCommand({getParameter: 1, newCollectionsUsePowerOf2Sizes: true})
              .newCollectionsUsePowerOf2Sizes,
          true);

test(1);