i have a dedicated server with celeron, 1G RAM running with cpanel. When i issued top command it says only 170Mb of RAM left?

i am posting the contents of ps aux command.

USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 2492 548 ? S Jan17 0:00 init [3]
root 2 0.0 0.0 0 0 ? SN Jan17 0:00 [ksoftirqd/0]
root 3 0.0 0.0 0 0 ? S< Jan17 0:00 [events/0]
root 4 0.0 0.0 0 0 ? S< Jan17 0:00 [khelper]
root 5 0.0 0.0 0 0 ? S< Jan17 0:00 [kacpid]
root 29 0.0 0.0 0 0 ? S< Jan17 0:00 [kblockd/0]
root 30 0.0 0.0 0 0 ? S Jan17 0:00 [khubd]
root 47 0.0 0.0 0 0 ? S Jan17 0:00 [pdflush]
root 48 0.0 0.0 0 0 ? S Jan17 0:00 [pdflush]
root 49 0.0 0.0 0 0 ? S Jan17 0:00 [kswapd0]
root 50 0.0 0.0 0 0 ? S< Jan17 0:00 [aio/0]
root 194 0.0 0.0 0 0 ? S Jan17 0:00 [kseriod]
root 417 0.0 0.0 0 0 ? S< Jan17 0:00 [ata/0]
root 418 0.0 0.0 0 0 ? S< Jan17 0:00 [ata_aux]
root 420 0.0 0.0 0 0 ? S Jan17 0:00 [scsi_eh_0]
root 421 0.0 0.0 0 0 ? S Jan17 0:00 [scsi_eh_1]
root 438 0.0 0.0 0 0 ? S Jan17 0:00 [kjournald]
root 1026 0.0 0.0 0 0 ? S< Jan17 0:00 [kauditd]
root 1698 0.0 0.0 1892 448 ? S<s Jan17 0:00 udevd
root 2038 0.0 0.0 0 0 ? S Jan17 0:00 [kjournald]
root 2039 0.0 0.0 0 0 ? S Jan17 0:00 [kjournald]
root 2040 0.0 0.0 0 0 ? S Jan17 0:00 [kjournald]
root 2041 0.0 0.0 0 0 ? S Jan17 0:00 [kjournald]
root 2042 0.0 0.0 0 0 ? S Jan17 0:00 [kjournald]
root 2775 0.0 0.0 2856 536 ? Ss Jan17 0:00 syslogd -m 0
root 2779 0.0 0.0 2960 376 ? Ss Jan17 0:00 klogd -x
named 2800 0.0 0.2 37612 2976 ? Ssl Jan17 0:00 /usr/sbin/named -
root 2843 0.0 0.0 3060 284 ? S Jan17 0:00 /usr/sbin/courier
root 2844 0.0 0.0 2024 600 ? S Jan17 0:00 /usr/libexec/cour
root 2864 0.0 0.0 2024 252 ? S Jan17 0:00 /usr/libexec/cour
root 2865 0.0 0.0 2024 252 ? S Jan17 0:00 /usr/libexec/cour
root 2866 0.0 0.0 2024 252 ? S Jan17 0:00 /usr/libexec/cour
root 2867 0.0 0.0 2024 252 ? S Jan17 0:00 /usr/libexec/cour
root 2868 0.0 0.0 2024 252 ? S Jan17 0:00 /usr/libexec/cour
root 2875 0.0 0.0 5144 380 ? Ss Jan17 0:00 rpc.idmapd
root 2938 0.0 0.0 2708 496 ? S Jan17 0:00 /usr/sbin/smartd
root 2947 0.0 0.0 2040 432 ? Ss Jan17 0:00 /usr/sbin/acpid
root 5024 0.0 0.1 4588 1048 ? Ss Jan17 0:00 /usr/sbin/sshd
root 5037 0.0 0.0 3580 748 ? Ss Jan17 0:00 xinetd -stayalive
root 5061 0.0 0.1 5912 1232 ? S Jan17 0:00 /bin/sh /usr/bin/
mysql 5093 0.0 1.4 106756 15224 ? Sl Jan17 0:00 /usr/sbin/mysqld
root 5126 0.0 0.5 9280 5264 ? S Jan17 0:00 chkservd
root 5138 0.0 0.0 2604 216 ? S Jan17 0:00 /usr/sbin/courier
root 5139 0.0 0.0 2324 480 ? S Jan17 0:00 /usr/lib/courier-
root 5146 0.0 0.0 1628 216 ? S Jan17 0:00 /usr/sbin/courier
root 5150 0.0 0.0 2628 476 ? S Jan17 0:00 /usr/lib/courier-
root 5156 0.0 0.0 2928 216 ? S Jan17 0:00 /usr/sbin/courier
root 5165 0.0 0.0 2808 480 ? S Jan17 0:00 /usr/lib/courier-
root 5179 0.0 0.0 2076 216 ? S Jan17 0:00 /usr/sbin/courier
root 5180 0.0 0.0 1692 480 ? S Jan17 0:00 /usr/lib/courier-
htt 5340 0.0 0.0 1976 128 ? Ss Jan17 0:00 /usr/sbin/htt -re
htt 5341 0.0 0.2 8124 3036 ? S Jan17 0:00 htt_server -nodae
canna 5357 0.0 1.6 19156 17360 ? Ss Jan17 0:00 /usr/sbin/cannase
root 5368 0.0 0.0 5556 920 ? Ss Jan17 0:00 crond
dbus 5647 0.0 0.0 3652 800 ? Ss Jan17 0:00 dbus-daemon-1 --s
root 5656 0.0 0.2 5804 2452 ? Ss Jan17 0:00 hald
root 5668 0.0 0.1 7396 2004 ? Ss Jan17 0:00 /usr/bin/perl /us
root 5700 0.0 0.0 1488 392 ? Ss Jan17 0:00 /usr/sbin/portsen
root 5721 0.0 0.0 2316 416 tty1 Ss+ Jan17 0:00 /sbin/mingetty tt
root 5722 0.0 0.0 2540 416 tty2 Ss+ Jan17 0:00 /sbin/mingetty tt
root 5723 0.0 0.0 2348 416 tty3 Ss+ Jan17 0:00 /sbin/mingetty tt
root 5724 0.0 0.0 3292 416 tty4 Ss+ Jan17 0:00 /sbin/mingetty tt
root 5725 0.0 0.0 2876 416 tty5 Ss+ Jan17 0:00 /sbin/mingetty tt
root 5726 0.0 0.0 2404 416 tty6 Ss+ Jan17 0:00 /sbin/mingetty tt
root 5727 0.0 0.0 2212 460 ttyS0 Ss+ Jan17 0:00 /sbin/agetty -L 9
root 7925 0.0 0.3 7100 3928 ? S 00:21 0:00 cpbandwd
mailnull 8084 0.0 0.0 9048 876 ? Ss 00:21 0:00 /usr/sbin/exim -b
mailnull 8089 0.0 0.0 7992 852 ? Ss 00:21 0:00 /usr/sbin/exim -t
root 8100 0.0 2.4 28736 25508 ? Ss 00:21 0:00 /usr/bin/spamd -d
root 8121 0.0 2.3 28736 24144 ? S 00:21 0:00 spamd child
root 8122 0.0 2.3 28736 24068 ? S 00:21 0:00 spamd child
root 8124 0.0 0.1 4392 1292 ? S 00:21 0:00 antirelayd
root 8213 0.0 0.6 10668 7080 ? SN 00:21 0:00 cpanellogd - slee
mailnull 8228 0.0 0.4 7300 4556 ? S 00:21 0:00 eximstats
mailman 8237 0.0 0.4 11852 4940 ? Ss 00:21 0:00 /usr/local/bin/py
mailman 8246 0.0 0.6 11104 6668 ? S 00:21 0:00 /usr/local/bin/py
mailman 8247 0.0 0.6 11212 6676 ? S 00:21 0:00 /usr/local/bin/py
mailman 8248 0.0 0.6 11872 6676 ? S 00:21 0:00 /usr/local/bin/py
mailman 8249 0.0 0.6 10788 6668 ? S 00:21 0:00 /usr/local/bin/py
mailman 8250 0.0 0.6 11672 6696 ? S 00:21 0:00 /usr/local/bin/py
mailman 8251 0.0 0.6 10936 6736 ? S 00:21 0:00 /usr/local/bin/py
mailman 8252 0.0 0.6 10096 6660 ? S 00:21 0:00 /usr/local/bin/py
mailman 8253 0.0 0.6 10816 6664 ? S 00:21 0:00 /usr/local/bin/py
nobody 8255 0.0 0.1 3796 1644 ? S 00:21 0:00 entropychat
root 8273 0.0 0.6 10360 6328 ? Ss 00:21 0:00 cPhulkd - process
root 8282 0.0 0.7 14512 7712 ? S 00:21 0:00 cpdavd - acceptin
root 8344 0.0 0.8 17716 8560 ? S 00:21 0:00 cpsrvd - waiting
root 14178 0.0 0.1 6768 1148 ? Ss 12:02 0:00 pure-ftpd (SERVER
root 14181 0.0 0.0 6428 676 ? S 12:02 0:00 /usr/sbin/pure-au
root 14208 0.0 0.8 19356 8296 ? Ss 12:04 0:00 /usr/local/apache
root 14209 0.0 0.4 8976 4892 ? S 12:04 0:00 /usr/bin/perl /us
root 14216 0.0 0.5 16192 5720 ? S 12:04 0:00 /usr/local/apache
nobody 14217 0.0 0.7 19568 8248 ? S 12:04 0:00 /usr/local/apache
nobody 14218 0.0 0.8 19616 8312 ? S 12:04 0:00 /usr/local/apache
nobody 14219 0.0 0.8 19624 8292 ? S 12:04 0:00 /usr/local/apache
nobody 14220 0.0 0.8 19624 8308 ? S 12:04 0:00 /usr/local/apache
nobody 14221 0.0 0.7 19600 8268 ? S 12:04 0:00 /usr/local/apache
nobody 14236 0.0 0.7 19492 8168 ? S 12:05 0:00 /usr/local/apache
nobody 14237 0.0 0.8 19608 8300 ? S 12:05 0:00 /usr/local/apache
nobody 14238 0.0 0.7 19620 8268 ? S 12:05 0:00 /usr/local/apache


should i worry? how do i fix it

You have nothing to worry about. In a few days you will have regular 10-20MB free memory. It's only the matter of server load and patience.

Seriously, memory is there to be used, not to be spared. Any decent OS will use all memory not used by processes to cache disk access thus making the computer more responsive. In the time of need, OS will recover all the memory it needs for specific task.

Set your mind at ease, run the command free, look at the amount of it that is cached and move on, RAM usage is normal in Linux. Until your box is thrashing and swapping the full amount of swap, there should be no worries. Like previously mentioned, RAM is to be used. If it's not going to be used, why install it. Linux is not Windows, it utilizes the RAM.