commit time in solr cloud

[Wei]

Hi,

In solr cloud we want to track the last commit time on each node. The
information source is from the luke handler:
 admin/luke?numTerms=0&wt=json, e.g.


   - userData:
   {
      - commitTimeMSec: "1504895505447"
      },
   - lastModified: "2017-09-08T18:31:45.447Z"



I'm assuming the lastModified time is when latest hard commit happens. Is
that correct?

On all nodes we have autoCommit set to 15 mins interval. One observation I
don't  understand is quite often the last commit time on shard leaders lags
behind the last commit time on replicas, some times the lag is over 10
minutes.  My understanding is that as update requests goes to leader first,
the timer on the leaders would start earlier than the replicas. Am I
missing something here?

Thanks,
Wei