в сервере стоит 4гб озу.
dmesg
Memory: 2574656k/4194304k available (2138k kernel code, 39808k reserved, 868k data, 240k init, 1698276k highmem)

ядро
2.6.18-1.2798.fc6 #1 SMP Mon Oct 16 14:37:32 EDT 2006 i686 i686 i386 GNU/Linux

cat /proc/meminfo
MemTotal:      2577316 kB
MemFree:       1164456 kB
Buffers:        107772 kB
Cached:         896160 kB
SwapCached:      47040 kB
Active:         971392 kB
Inactive:       360416 kB
HighTotal:     1698276 kB
HighFree:       575264 kB
LowTotal:       879040 kB
LowFree:        589192 kB
SwapTotal:     4096552 kB
SwapFree:      3895020 kB
Dirty:              64 kB
Writeback:           0 kB
AnonPages:      311692 kB
Mapped:         137372 kB
Slab:            52920 kB
PageTables:       8100 kB
NFS_Unstable:        0 kB
Bounce:              0 kB
CommitLimit:   5385208 kB
Committed_AS:  1775728 kB
VmallocTotal:   114680 kB
VmallocUsed:      4856 kB
VmallocChunk:   108552 kB
HugePages_Total:     0
HugePages_Free:      0
HugePages_Rsvd:      0
Hugepagesize:     4096 kB

cat /boot/config-2.6.18-1.2798.fc6 | grep 4G
CONFIG_HIGHMEM4G=y

почему не вся память используется?