1. In the cache configuration dialog, click the Advanced L2 Cache Options button.
2. Uncheck the Individual Read/Write Cache Space option if you want the whole cache space shared for both reading and writing. Or, move the slider to specify a ratio of writing cache space if you want to separate reading and writing cache space.
Cache contents stored in level-2 storage are persistent even when storage devices are powered off. This brings up potential problems. For example, suppose that a level-2 storage volume was plugged out by intention or accident and some time later it is plugged in again, if source disk contents were modified during this period, cache contents may become outdated. In order to avoid such kind of problems, PrimoCache implements a mechanism to make sure that cache contents keep identical to source disks, by tracing and updating some Windows registry flags. When PrimoCache detects that cache contents are possibly outdated, it will remove all existing cache contents. This also means that Windows partition shall not be write-protected, otherwise PrimoCache cannot update registry flags and will think level-2 cache contents are outdated and remove them each time computer boots up. The same thing happens when Windows was abnormally shutdown due to crash, hang or power shutdown, because PrimoCache had no chance to update registry flags.
Though PrimoCache has the built-in verification mechanism as described above, it cannot prevent the case of "offline modification". "Offline modification" means that data in source disk or cache storage are modified when PrimoCache is not running. Given below is an example of "offline modification". Assume that you have two computers and a disk (here we call it X) was installed in one computer (here we call it A), you plugged out the disk X and installed it on the other computer and changed its contents, such as copying, overwriting, or deleting something to this disk. Then you installed the disk X back on the computer A. For the computer A, the disk X was "offline modified". Here is another example. Assume that you have a computer with dual-boot operating systems. If the disk X in one operating system (here we call it A) was modified in another operating system, then for the system A, the disk X was "offline modified". Because PrimoCache can do nothing when it is not running, it is the user's responsibility to avoid "offline modification".