Feature Request: Support compress cache mode

[sunday]

As an enthusiast PrimoCache, I would like to use compressed mode for caching.
In a modern PC / Server, CPU has more power, I think you can add the compression cache mode like Windows disk compression feature to save space.
If you add this feature, I think it would be an unique and unprecedented feature in the similar product. Anyway, speed compression / decompression is faster than the speed of read / write directly on hard drives ?
This feature may take an additional less 5% CPU but gain 50% or more space, it can be accepted ?

Thanks for attention.

[Support]

Thanks for the suggestion!

[idefix44]

I don't think that it's a good idea.
Because the PrimoCache main purpose isn't to gain space on the L2 SSD disk, but to gain speed on the HDD targeted disk.
How read/write + compress/decompress cant it be faster than only read/write?

[InquiringMind]

It wouldn't be faster on a per-operation basis, but would allow for more data to be cached which *might* improve performance overall. NTFS has its own compression which is pretty CPU-light and most modern desktop systems have plenty of CPU cycles to spare.

However it might only benefit L1 (RAM) rather than L2 (SSD) caches.

[sunday]

I totally agree with "InquiringMind" that this mode should be applied in the L1 cache (RAM).
In my server, CPU rarely exceeded 65%, so there is excess power to use.
While using more RAM is a big problem because it is used for many other applications.

[anocs]

Using some nowadays fast compression algorithms e.g. LZ4 (ZHUFF) / SNAPPY / LZF / LZO it might be brilliant idea to have cache compressed...

[InquiringMind]

...it might be brilliant idea to have cache compressed...

The downside is that much of the data in the cache is unlikely to compress well (executable files, Windows DLLs, etc) with fast algorithms. The most easily compressible items will tend to be frequently updated (so less likely to benefit from caching at all) application data like word processor documents, spreadsheet files or saved games. And many large data files (video, music, JPG/PNG graphics, ISO images) are compressed already so wouldn't benefit.

I wouldn't rule this feature out, but I think that it may have less real benefit than many here are hoping for. Some type of dynamic compression (where the amount is adjusted according to available CPU) might be best as an option for L1 (RAM) caching.

[DMatter]

+1 for a standard PC the RAM size is not 16Gb or +

good compress + dynamic size of ram cahce is good for me