high-water-disk-pct 
Data will be evicted if the disk utilization is greater than this specified percentage.
default 50

high-water-memory-pct 
Data will be evicted if the memory utilization is greater than this specified percentage.
default 60


stop-writes-pct 
Disallow writes (except deletes, replica writes and migration writes) when memory utilization (tracked under memory_used_bytes) is above this specified percentage.
default 90

min-avail-pct
Disallow writes (except deletes, replica writes and migration writes) when device_available_pct on one of the devices configured for the namespace is below this specified percentage.
default 5

min-avail-pct relates to the minimum available amount of space on SSDs 
min-avail-pct 与ssd上的最小可用空间有关

Avail%   
% of write blocks available, least value for nodes across cluster
data-in-memory 模式该值无效

某客户因为该值小于 5% 触发 stop-writes （磁盘和内存都未达到阈值）
AMC stop-writes 次数好像不准 ，一直为0

high-water-disk-pct  调低 ， 触发逐出 ， 


后台线程 expire-threads   负责逐出


Records with TTL 0 will not be evicted. Data that is set to expire first, by TTL bucket, will be first to be evicted.
ttl0记录将不会被驱逐。由TTL bucket首先设置为过期的数据将首先被驱逐。



 aerospike中的过期驱逐和停止写入机制