ubuntu - Any reason not to use Redis 32bit (as opposed to 64bit) except for the 4GB limit? -

i'm concerned mem box on among other things run couple of redis instances. thefore i'm thinking moving redis 32bit since should save me quite bit of ram.

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redis compiled 32 bit target uses lot less memory per key, since pointers small, such instance limited 4 gb of maximum memory usage. compile redis 32 bit binary use make 32bit. rdb , aof files compatible between 32 bit , 64 bit instances (and between little , big endian of course) can switch 32 64 bit, or contrary, without problems.

as said in quote, 4gb max redis instance on 32 bit i'm making sure don't hit this. use multiple redis instances each stay below 4gb limit, guess not problem (?)

any other reason, such performance possibly, should out for?

using multiple 32 bits redis instances works well. there few drawbacks need consider though:

• most people run 64 bits version, 32 bits version less tested , deployed. makes less reliable, since increases hit undetected bug.

• some operations less efficient in 32 bits. instance bitop, bitcount operations should more efficient when run on 64 bits cpu.

• it difficult set memory limit. setting maxmemory parameter tricky because have consider more size of data (but internal communication buffers , master/slave replication buffers, i/o buffers, etc ...). if optimistic (i.e. if have set maxmemory close 4 gb), have random crash when redis memory saturated.

you may want read salvatore said it:

https://groups.google.com/forum/#!topic/redis-db/thcvjdmrqce