[BUG] Caching avg total bytes and avg free bytes inside ClusterInfo

[RS146BIJAY]

Describe the bug

Description

In case disk usage of a particular node is not populated inside ClusterInfo (due to an underlying issue), we use the average usage for all nodes as the usage for this node inside DiskThresholdDecider. For calculating this value, right now we are iterating through all the diskUsages of every node inside DiskThresholdDecider to calculate total sum and divide by the total number of nodes. Since this computation is performed for each node during shard allocation, it becomes computationally expensive.

Related component

Indexing:Replication

To Reproduce

Create 500k shards on a setup with 1000 data nodes and 3 master nodes.

Expected behavior

Do an offline calculation of Average total bytes and Average free bytes and cache it inside ClusterInfo.

Additional Details

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• OS: [e.g. iOS]
• Version [e.g. 22]

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