Can't start a new cache task over about 48900 MB

[edv]

I am using Windows Server 2008R2 Enterprise with 64 GB of system memory (task manager shows 65513 MB total, 61790 MB available, 61054 MB free at the moment), and I am unable to start a new cache task under PrimoCache v0.9.1 with a read cache size of more than about 48900 MB (the exact number that causes failure fluctuates by 20 MB or so - sometimes 48880 works and sometimes not). When the cache does not start I see a dialog that simply says, "Failed to start cache." It does not matter if I use a read-only or read-write cache.

I used the various earlier FancyCache betas with cache sizes of 55 GB or so fairly often on this same server.

The PrimoCache window says "Memory Overhead 4.71 GB" and when I start a cache task using 48000 MB of memory, the "OS Managed Memory - Free / Total (MB)" is listed as 8861/65513, which seems like there would be quite a bit more room for extra cache allocation.

[InquiringMind]

Hi Edv,

Try a larger block size for your cache (I've found 64K to be the sweet spot with a 7GB cache, but you may wish to experiment to find the ideal for your system). This reduces the overhead and should allow for a larger cache setting.

[edv]

Thank you for the suggestion; if I change the block size to 64K, I can start a cache of 53000 MB, but no higher (which is about the difference in the overhead, but still the "OS Free Memory" lists as around 8000 MB when the cache is started, which seems like quite a bit of memory to be unable to use for the cache. Shouldn't PrimoCache know how much memory it could allocate properly without my having to guess? It's also a bit of a nuisance that the settings are all reset to the default every time I want to test a new cache configuration (re-selecting the block size, write defer latency, etc. every time).

[InquiringMind]

PrimoCache allows block sizes up to 512KB - do any of the larger ones allow you to allocate more memory? If not, then you may have encountered an internal limitation.

As for suggesting block sizes, the default size could be better chosen and the error message should be more informative (I found it unhelpful too). And yes, the ability to save a cache profile (as is currently possible with Primo Ramdisk) would be useful.

However this is beta software so an imperfect UI is probably to be expected. Stability and reliability should be Romex's priority and while PrimoCache has been perfectly stable for me,some others have reported problems here.