Strings
A String value can be at max 512 Megabytes inlength.
Lists
The max length of a list is 232 - 1 elements(4294967295, more than 4 billion of elements per list).
Sets
The max number of members in a set is 232 - 1(4294967295, more than 4 billion of members per set).
Hashes
Every hash can store up to 232 - 1 field-value pairs(more than 4 billion).
Sortedsets
Redis Sorted Sets are, similarly to Redis Sets, non repeatingcollections of Strings. The difference is that every member of aSorted Set is associated with score, that is used in order to takethe sorted set ordered, from the smallest to the greatest score.While members are unique, scores may be repeated.
What is the maximum number ofkeys a single Redis instance can hold? and what the max number ofelements in a List, Set, Ordered Set?
In theory Redis can handle up to2^32 (4 bilions)keys, and was tested in practice to handle at least250 million of keys per instance. We are working in order toexperiment with larger values.
Every list, set, and ordered set,can hold 2^32 elements.
In other words your limit islikely the available memory in your system.