Fresh Debian Squeeze (6) Installation - Very High Ram Usage
We've got a new server provisioned, and are experiencing high ram usage, without information on the usage in either htop / top nor in a python memory script found (http://www.pixelbeat.org/scripts/ps_mem.py). Here is the output from free -m:
total used free shared buffers cached
Mem: 7195 1347 5848 0 3 28
-/+ buffers/cache: 1315 5879
Swap: 3813 0 3813
And from top, sorted by memory usage:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1586 root 20 0 200m 14m 1836 S 0 0.2 0:00.75 xend
1585 root 20 0 95892 9.9m 832 S 0 0.1 0:00.00 xend
1855 root 20 0 51728 2996 2368 S 0 0.0 0:00.00 sshd
1822 ntp 20 0 38332 2176 1596 S 0 0.0 0:00.03 ntpd
1858 psadmin 20 0 17728 1932 1436 S 0 0.0 0:00.00 bash
1071 root 20 0 52416 1852 1032 S 0 0.0 0:00.02 rsyslogd
1857 psadmin 20 0 51880 1396 756 S 0 0.0 0:00.00 sshd
1866 psadmin 20 0 19064 1364 1000 R 0 0.0 0:00.04 top
1564 root 20 0 49168 1140 592 S 0 0.0 0:00.00 sshd (etc)
And the aforementioned python script which says what applications are using what:
Private + Shared = RAM used Program
180.0 KiB + 71.5 KiB = 251.5 KiB xenconsoled
228.0 KiB + 32.0 KiB = 260.0 KiB acpid
204.0 KiB + 58.0 KiB = 262.0 KiB init
252.0 KiB + 75.5 KiB = 327.5 KiB cron
332.0 KiB + 44.0 KiB = 376.0 KiB dbus-daemon
380.0 KiB + 53.5 KiB = 433.5 KiB xenstored
556.0 KiB + 138.0 KiB = 694.0 KiB sudo
612.0 KiB + 255.0 KiB = 867.0 KiB getty (6)
604.0 KiB + 582.0 KiB = 1.2 MiB udevd (3)
1.1 MiB + 103.5 KiB = 1.2 MiB rsyslogd
956.0 KiB + 267.5 KiB = 1.2 MiB ntpd
1.2 MiB + 73.0 KiB = 1.3 MiB bash
1.5 MiB + 1.3 MiB = 2.8 MiB sshd (3)
16.2 MiB + 3.8 MiB = 20.0 MiB xend (2)
---------------------------------
31.0 MiB
=================================
Private + Shared = RAM used Program
So, two questions really:
1) What is this RAM going to?
2) Why would I be seeing only 7195MB of RAM from an installed 8GB?
This is on a Dell Poweredge R210, with SAS drives in RAID0.
Any help with this would be very greatly appreciated!
Solution 1:
Transpires that it was the same issue seen here: Debian Squeeze and available memory (1GB absent), the Xen kernel makes ~1GB 'absent' shown in dmesg.
Updated question with specifics: Xen Kernel on Debian Squeeze making 1GB memory 'absent'