Romex Software Forum

Here's Scenario 1:

PC 1 has a bunch of HDDs in it. Its HDDs are connected to PC 2 via ethernet so that PC 2 can access them as if they were local drives. PC 2 is running Primocache.

Can PC 2 use its own RAM and SSD to cache the drives connected from PC 1? Can PC 1 ALSO run Primocache to have RAM and SSD cache the HDDs before sending the requested data to PC 2?

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Here's Scenario 2:

PC 1 has 128GB of RAM. It is using PrimoRAMDisk to create a 124GB RAMDisk. Its entire purpose is to run that RAMDisk. That RAMDisk is being sent to PC 2 via ethernet. PC 2 uses that RAMDisk as an L2 cache for an HDD or SSD.

Can this be done? Obviously, speeds will be limited by ethernet ports, but Defer Write can still be a big benefit (although risky in the event of power loss causing data loss).

Scenario 1: Yes, this is possible. However, the cache will be removed if PC1 HDDs are disconnected. You need to turn off PC2 first in this scenario.
Scenario 2: This scenario is not considered and tested before. It is not recommended that using a ramdisk as L2 cache because L2 cache is designed for persistent cache, while an internet ramdisk is not stable.

Plenty of people (including me) are using Primocache to cache a iSCSI mount from a slower NAS.
The Microsoft iSCSI-initiator is built right into every Windows version. Once you have the iSCSI target mounted, Primocache will see it as a local disk.

Forget about using Windows and Primocache on your PC1 and install something like TrueNAS on it.
TrueNAS will use all memory it has to cache disk data, you can even set up L2ARC as a second tier SSD cache.
Hot data comes out of the fast SSD on your local machine, warm data will come out of the memory of the NAS and cold data will be read from HDD.
As a bonus, TrueNAS can keep data in memory and on disk compressed which is something Primocache cannot do. (*hint hint Romex* )

In my setup, local SSD can push 5GB/sec from Primocache L2. If it can fetch it from TrueNAS memory or L2ARC, I still get 1GB/sec over a 10gbit LAN.
Worst case it has to read data from the HDD pool which can also do 1GB/sec sequential but with much higher latency.

I advise against using defer write, sooner or later you are going to have a network interruption and you will lose data. (Don't say we didn't warn you)