Reducing memory usage

[kilburn]

Tracking memory usage is not a simple task, and dcreation gave you an initial hint of it.

First of all, assuming that you have no SWAP space, the virtual memory (VIRT) used by a process is completely irrelevant.
Next, the most important figure is the physical memory being used (RES column), which says that your apache instances are consuming approximately 5mb each).

Nevertheless, this is not entirely true, as part of this memory is shared with other processes (those that use the same libraries). A hint about the amount of memory that *might* be shared with other processes is shown in the SHR column. For your apache case, this column shows that approx. 1.3mb of each apache process are potentially being shared (not just among the apache process, but with any other program using the same libs).

Finally, adding the RES value of all your processes gives you a *worst case* (this is, considering that no memory is shared between processes at all which is NOT the case) of 180mb being used by your system.