We are using ES 2.1.0, quad core virtual machines, 12 GB ram, SAN disks.
We have a process where we will create a new index and when it is done point an alias at it.
Then later, we have to make a new index and again when it is done, point an alias and delete the old version.
We do this over and over probably a couple hundred times a day for different indices.
When the cluster has first started up, it will complete a large index of 1m+ records in about 20 minutes.
However, after the cluster runs for about 5 days to a week... the same type of index on the same type of data will go to 1 hr 20 minutes.... even indexes that usually take a couple minutes to generate will take 20+.
The fix for it is to do a rolling restart of the cluster. This involves only restarting the ES Service on each node, not a reboot (we run on Windows).
Does anyone know why this would occur? What could happen that makes ES start to index a whole new index more slowly?