Romex Software Forum

Hello, I'm a little puzzled by Write cache.
How does it work when Defer Write is disabled?
Tooltip help comments suggest writes are bypassing the cache altogether.
Are writes therefore being copied into cache by default?
I imagine write cache is less use full than read cache so,
Under what circumstance is it beneficial ?
What is a good % for write cache ?

Caching writes with write-through cache can be tad useful if you read a good lot of the written data either frequently or just after writing. Software compilation is a good example: first compiler writes a bloody lot of object files, then linker starts to read and process them. If they fit into OS cache, it's ok, but if they don't, here's where PrimoCache shines

The only benefit I can see is that if the write cache storage isn't needed due to low writing activity, reads will be made from the cache. Defer Write makes a huge difference when you have heavy simultaneous writing to multiple files. As far as I can tell, PrimoCache essentially sequentializes the writing. It's not documented to do so and I don't know that it does, but the results indicate this. I expect that this would only apply for a drive that is not fragmented (and/or has a lot of continuous free space.) I find that even with plenty of OS cache available, PrimoCache is far superior at doing this.

Write cache is to store write-data into cache so if these data is requested to be read back later it can be read from cache instead of source disk. Meanwhile, if Defer-write is not enabled, write-data will also be written to disks immediately.

I now understand. Thanks all, much appreciated.