Expected upgrade times?

Elastic Stack Elasticsearch
1

We are currently upgrading from ES 1.6 to 2.1.

ES is taking about 2 minutes per gigabyte of index data, according to the log timestamps.

I've turned off cluster.routing.allocation.enable and done a /_flush/synced as instructed in the upgrade docs on each node in the cluster.

This seems too slow; what should I be investigating to explain the slowness?

2

It depends, how much data do you have, what sort of disk, what node resources?

3

For each node, its about 250GB of index data and 3G memory.

The disk is a RAID using SATA drives, though I'm not as familiar with that part of the stack.

4

That's not a lot of resources, but maybe increasing some of these allocation settings will help - cluster.routing.allocation.node_concurrent_recoveries and indices.recovery.concurrent_streams.