CentOS memory allocation

Question

I was running my VPS with CentOS on 1G memory, but I saw the memory was getting "full" so I had 1G extra installed.

This VPS is one I rent at a hosting company. That company did most of the configuration for me on installation of the VPS. They also installed DirectAdmin and handled all domain/DNS issues.

I only installed certain user/FTP accounts and uploaded all my production websites. This servers hosts: 5 small static PHP websites, 2 wordpress websites, 1 Magento webshop, a testing evirment for myself and all e-mail accounts for each website.

My goal is to enhance the server performance.

I looked at various of guides on the internet. I broke allot of things and had to fix them afterwards, so I learned as I was going. I found out that I need to follow some correct guides/tutorials and need to make sure to follow only CentOs related stuff.

ulimit -a and free -m command tell the following:

[root@1332 etc]# ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 32365
max locked memory       (kbytes, -l) 32
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 32365
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited
[root@1332 etc]# free -m
             total       used       free     shared    buffers     cached
Mem:          2026        990       1036          0        129        620
-/+ buffers/cache:        240       1786
Swap:         2047          0       2047

So I have some extra free memory

top - 14:35:36 up  4:15,  1 user,  load average: 0.57, 0.49, 0.46
Tasks: 169 total,   1 running, 168 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.1%us,  0.0%sy,  0.0%ni, 99.8%id,  0.0%wa,  0.1%hi,  0.0%si,  0.0%st
Mem:   2075000k total,  1016716k used,  1058284k free,   133924k buffers
Swap:  2097144k total,        0k used,  2097144k free,   637168k cached

I did a restart of the server, thats probably why everything is looking great.

I changed my.cnf settings to the following:

[mysqld]
local-infile=0
skip-locking
query_cache_limit=2M
query_cache_size=64M
query_cache_type=1
max_connections=500
interactive_timeout=100
wait_timeout=120
connect_timeout=10
thread_cache_size=128
key_buffer=384M
join_buffer=8M
max_allowed_packet=16M
table_cache=1024
record_buffer=1M
sort_buffer_size=2M
read_buffer_size=2M
max_connect_errors=10
# Try number of CPU's*2 for thread_concurrency
thread_concurrency=6
myisam_sort_buffer_size=64M
server-id=1

[safe_mysqld]
err-log=/var/log/mysqld.log
open_files_limit=8192

[mysqldump]
quick
max_allowed_packet=16M

[mysql]
no-auto-rehash
#safe-updates

[isamchk]
key_buffer=64M
sort_buffer=64M
read_buffer=16M
write_buffer=16M

[myisamchk]
key_buffer=64M
sort_buffer=64M
read_buffer=16M
write_buffer=16M

[mysqlhotcopy]
interactive-timeout

I noticed that I don't have any innoDB settings here. Probably because they aren't installed or because of the presence of DirectAdmin or because my hoster doesn't use that.

So, some questions:

1. Are my.cnf settings "correct" for having the best settings? (at this moment)

2. Are there any other settings I need to worry about?

3. Are there any performance tweaks I still need to do for Magento? (I tried installing APC or Xcache, but that didn't do much)

4. I installed REDIS, but is it normal that I don't "feel" anything in performance because of that?