I have 4 data nodes with 25 Tb on each for a total of 100Tb of storage.
I want to change the cluster threshold because, by default, the option
cluster.routing.allocation.disk.watermark.flood_stage is at 95%.
That will mean I lost 1 250 Gb of data per node and so 5Tb in total
I would like to change it but I don't know the best practice to have an optimized value.
I have 2 idea :
- Based on my bigest index size (100Gb on primary index)
cluster.routing.allocation.disk.watermark.low : 200gb cluster.routing.allocation.disk.watermark.high : 150gb cluster.routing.allocation.disk.watermark.flood_stage: 120gb
Total losted space : 120x4=480gb
- Based on the fact that my machines use LVM and risk of a complete crash is quite limited.
cluster.routing.allocation.disk.watermark.low : 50gb cluster.routing.allocation.disk.watermark.high : 20gb cluster.routing.allocation.disk.watermark.flood_stage: 15gb
Total losted space : 15x4=60Gb
Is my logic correct ?