深入了解Redis看看数据量有多大（如何查看redis数据量）

Redis或REmote DIctionary Server是一个开源的，高性能的键值对存储数据库，支持多种类型的数据结构。它以内存操作为主，通过多路IO复用，支持更大的内存数据量，使得Redis能够在比其他Nosql数据库（如YSQL、MongoDB）更具性能优势的情况下处理更多的数据量。

Redis能够处理的最大数据量，主要由硬件类型和操作系统决定，一般而言，根据实际系统状况，有32GB、64GB和128GB等几种可选择的配置类型。当然，也要考虑其他因素，比如Redis支持AOF（append-only-files）日志缩减策略，用来存储写进数据库里的内容，以减小RDB持久化数据量，还有通过压缩等方式来节省空间。

另外，根据对Redis的灵活配置，我们还可以调节其缓存大小，以确保Redis在处理较大体积数据时不会出现卡顿的情况，可以在`redis.conf`中设置`maxmemory`的大小：

“`bash

#

# maxmemory

#

# Set a memory usage limit to the specified amount of bytes.

# When the memory limit is reached Redis will try to remove keys

# according to the eviction policy selected (see maxmemory-policy).

#

# If Redis can’t remove keys according to the policy, or if the policy is

# set to ‘noeviction’, Redis will start to reply with errors to commands

# that would use more memory, like SET, LPUSH, and so on, and will continue

# to reply to read-only commands like GET.

#

# This option is usually useful when using Redis as an LRU cache, or to set

# a hard memory limit for an instance (using the ‘noeviction’ policy).

#

# WARNING: If you have slaves attached to an instance with maxmemory on,

# the size of the output buffers needed to feed the slaves are subtracted

# from the used memory count, so that network problems / resyncs will

# not trigger a loop where keys are evicted, and in turn the output

# buffer of slaves is full with DELs of keys evicted triggering the deletion

# of more keys, and so forth until the database is completely emptied.

#

# In short… if you have slaves attached it is suggested that you set a lower

# limit for maxmemory so that there is some free RAM on the system for slave

# output buffers (but this is not needed if the policy is ‘noeviction’).

#

maxmemory 32GB

由于Redis在处理较大体积数据时早已可以做到良好的性能表现，所以在理论上可以处理更大规模的数据量，只要硬件设备满足条件即可。可以看到，Redis作为一种高效缓存存储数据库来说，在数据量比较大的情况下，其优势便能完全体现出来，是很值得一提的技术。