our redis has one master and two slaves. master is used for writing and slaves for read
the load of two slaves are not balanced.
one of the slaves shows memery increasion and reaches 64G in nearly one week
is it a known issue?

info as below:
redis_version:2.4.17
redis_git_sha1:00000000
redis_git_dirty:0
arch_bits:64
multiplexing_api:epoll
gcc_version:3.4.5
process_id:12810
run_id:4572562df85e606f2b104c91a4f12d384aa442dd
uptime_in_seconds:935738
uptime_in_days:10
lru_clock:320363
used_cpu_sys:15491.18
used_cpu_user:40038.00
used_cpu_sys_children:1145.14
used_cpu_user_children:6828.54
connected_clients:144
connected_slaves:0
client_longest_output_list:1002795
client_biggest_input_buf:0
blocked_clients:0
used_memory:30112603920
used_memory_human:28.04G
used_memory_rss:27719020544
used_memory_peak:30112857704
used_memory_peak_human:28.04G
mem_fragmentation_ratio:0.92
mem_allocator:jemalloc-3.0.0
loading:0
aof_enabled:1
changes_since_last_save:5279
bgsave_in_progress:0
last_save_time:1366352293
bgrewriteaof_in_progress:0
total_connections_received:1157
total_commands_processed:1405498323
expired_keys:0
evicted_keys:0
keyspace_hits:1354193664
keyspace_misses:25036293
pubsub_channels:0
pubsub_patterns:0
latest_fork_usec:365363
vm_enabled:0
role:slave
aof_current_size:1160106744
aof_base_size:66
aof_pending_rewrite:0
aof_buffer_length:0
aof_pending_bio_fsync:0
master_host:10.36.72.40
master_port:8615
master_link_status:up
master_last_io_seconds_ago:0
master_sync_in_progress:0
slave_priority:100
db0:keys=1166985,expires=2
aof_global_offset:6324984906
sync_delay_mstime:4
server_version:1