Low memory on VPS

I have a VPS account that has memory issues. It runs several WordPress sites, but they all have low traffic. For all sites in total, the server receives about 500 visitors per day. This causes the databases to stop responding and sites to drop.

The "top" command was not found, but I ran the following command to get what I succeeded. The server was rebooted yesterday.

[root@vps2096 bin]# cat /proc/meminfo
MemTotal:        1048576 kB
MemFree:            9584 kB
Cached:           122252 kB
Buffers:               0 kB
Active:           552524 kB
Inactive:         454528 kB
Active(anon):     488708 kB
Inactive(anon):   396092 kB
Active(file):      63816 kB
Inactive(file):    58436 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:        884800 kB
Shmem:              3820 kB
Slab:              31924 kB
SReclaimable:      13764 kB
SUnreclaim:        18160 kB

It seems that 1 gigabyte of RAM should be more than capable of running multiple sites. I am running Linux version 2.6.32-042stab084.17 with Plesk, not Cpanel.

It seems that the number of AnonPages is large, but I do not know what it is.

, , ? W3 Total Cache WP- ? ?

!