Hi,
all UBC configuration parameters should obey the consistency rules which are described at the page
http://wiki.openvz.org/UBC_consistency_check
It's just a simple math exercise
For example
Let's assume that there are exist two configuration examples.
Each of them should obey the inequalities that are described in a page mentioned above i.e.
privvmpages_1_bar >= vmguarpages_1_bar
privvmpages_2_bar >= vmguarpages_2_bar
If
privvmpages_3_bar = a_1*privvmpages_1_bar + a_2*privvmpages_2_bar
vmguarpages_3_bar = a_1*vmguarpages_1_bar + a_2*vmguarpages_2_bar
a_1 + a_2 = 1, a_1 >= 0, a_2 >= 0
then the consistency rule is still being held
privvmpages_3_bar >= vmguarpages_3_bar
So, the third configuration which is obtained as
[THIRD_CONFIGURATION] = a_1*[FIRST_CONFIGURATION] + a_2*[SECOND_CONFIGURATION]
a_1>=0, a_2>=0, a_1 + a_2 = 1
obey the consistency rule.
Consider another rule
tcprcvbuf_1_bar >= 64
tcprcv)buf_2_bar >= 64
So, the third configuration which is obtained as
[THIRD_CONFIGURATION] = a_1*[FIRST_CONFIGURATION] + a_2*[SECOND_CONFIGURATION]
a_1>=0, a_2>=0, a_1 + a_2 = 1
should obtain this rule too
tcprcvbuf_3_bar = a_1*tcprcvbuf_1_bar + a_2*tcprcv)buf_2_bar >= a_1*64 + a_2*64 = 64*(a_1 + a_2) = 64
because a_1 + a_2 = 1.
But subtraction doesn't guarantee that all rules are preserved.
Example
5 > 3, 4 > 1 but (5 - 4) < (3 - 1) because 1 < 2
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