Redis using high memory with small data set - database

Question

I'm running redis-server and according to prstat it's utilizing 3721M of memory. When I run info in redis-cli, I get this for memory:
used_memory:8739028
used_memory_human:8.33M
used_memory_rss:8739028
mem_fragmentation_ratio:1.00
This is running on a 2GB cloud instance, so my memory utilization is always over. However, even when I flushall on redis it doesn't seem to effect the memory consumption.
Could this be do to a setting that maybe is allocating memory or any idea why redis is using so much over my actual data?
Thank you!
EDIT:
Also just to add, I'm running the same setup (application/redis) on another instance and the memory consumption is only 554M with used_memory_human:5.68M of data.
Response from pmap:
[root#]# pmap -x 27425
27425: /opt/local/bin/redis-server /opt/local/etc/redis.conf
Address Kbytes RSS Anon Locked Mode Mapped File
08046000 8 8 8 - rw--- [ stack ]
08050000 208 160 - - r-x-- redis-server
08093000 8 8 4 - rwx-- redis-server
08095000 3807836 3804160 3764928 - rwx-- [ heap ]
FE9BD000 12 12 - - r-x-- libpthread.so.1
FEAF0000 456 456 - - r-x-- libnsl.so.1
FEB72000 8 8 4 - rw--- libnsl.so.1
FEB74000 20 16 4 - rw--- libnsl.so.1
FEBA0000 304 304 - - r-x-- libm.so.2
FEBFB000 16 16 - - rwx-- libm.so.2
FEDA0000 4 4 - - r--s- dev:531,392 ino:3736139179
FEDB0000 4 4 - - rwxs- [ anon ]
FEDC0000 24 12 8 - rwx-- [ anon ]
FEDD0000 4 4 4 - rwx-- [ anon ]
FEDE0000 1216 1216 - - r-x-- libc.so.1
FEF10000 36 36 24 - rwx-- libc.so.1
FEF19000 8 8 4 - rwx-- libc.so.1
FEF20000 4 4 4 - rwx-- [ anon ]
FEF30000 56 56 - - r-x-- libsocket.so.1
FEF4E000 4 4 - - rw--- libsocket.so.1
FEF50000 4 4 4 - rwx-- [ anon ]
FEF60000 4 4 - - r-x-- libdl.so.1
FEF70000 4 4 - - r--s- ld.config
FEF80000 4 4 4 - rw--- [ anon ]
FEF90000 4 - - - rw--- [ anon ]
FEFA0000 4 4 4 - rwx-- [ anon ]
FEFB0000 4 4 - - rwx-- [ anon ]
FEFB7000 208 208 - - r-x-- ld.so.1
FEFFB000 8 8 4 - rwx-- ld.so.1
FEFFD000 4 4 - - rwx-- ld.so.1
The limits has nothing enabled in the config, here's virtual memory and advanced:
VIRTUAL MEMORY
vm-enabled no
vm-swap-file /tmp/redis.swap
vm-max-memory 0
vm-page-size 32
vm-pages 134217728
vm-max-threads 4
ADVANCED CONFIG
hash-max-zipmap-entries 512
hash-max-zipmap-value 64

Answer 1

Question is a bit old but I had this issue before. If I remember correctly, I shutdown my redis instance, deleted the RDB file if applicable and restart redis. If don't want to remove the RDB file because it contains data you need, I do NOT recommend this. You can try to DEL what you can, then do a SAVE (I believe redis does SAVE when it's shutdown so that might be redundant) and then restart.
It would be good time to upgrade redis to latest stable if you haven't.