Romex Software Forum

Hi,

i wonder how primo cache determines if the L2 (ssd) cache is valid or invalid, in the case of a pause or removable blockdevice? I assume this is not supported, but how does primocache know for sure that the cache content is actually what is on the physical disk?

Lets assume you pause primo cache or disconnect a iSCSI target and than change something on the filesystem, than restart primo cache?

thx
Andy

PS: The basic question is can primo cache work on a mutable iSCSI target, that gets connected/disconnected from different PC's (one with exclusive write rights) over the LAN, without corrupting the filesystem?

I remembered that in v2.0 each time an iSCSI target gets disconnected, PrimoCache automatically invalidates corresponding L2 cache whether PrimoCache is paused or not.
I will ask our testing colleagues for confirmation on next working day.

support wrote:in v2.0 each time an iSCSI target gets disconnected, PrimoCache automatically invalidates corresponding L2 cache whether PrimoCache is paused or not.

Confirmed.

Of course, if you "offline" change the content of the iSCSI target, then there's no way to know that. "Offline Modification" shall be avoided by users. See http://www.romexsoftware.com/en-us/prim ... cache.html

Here is an example of "offline modifiction" in your case.
Let's say Windows system A in which PrimoCache is installed and L2 is enabled was connected to a iSCSI target, then Windows A is shutdown. Next, you mount this iSCSI target and modify its content in Windows B. Now you shutdown Windows B and restart Windows A. Then PrimoCache don't know the change of iSCSI target and its L2 cache content is outdated, you may get errors in this scenario.

Here is anoher thing shall be avoided. If a iSCSI target can be connected by multiple initiators (usually this only happens on clustering systems), you shall not enable L2 for this target.

Oki thx for the info, i was assuming that this will be the case, but at least the L2 cache gets invalidated on disconnect from the initiator.

Btw will the L2 cache be retained upon sleep/resume S4/5 and system restart? I'm not familiar how windows internally handles these cases for a connected iSCSI target? Will a reboot still count the target as "connected" so the L2 cache is available on reboot?

thx
Andy