Hoping for some help more knowledgable than me on this.

I’ve spent years with my RAID 5 array being insanely slow to write to (15 MB/sec) and have just grit my teeth and dealt with it. I finally learned about the “write through” vs “write back” - I tested the “always write back” setting.

On the previous settings, files would start at 450 MB/sec and quickly dip to 15 and stay there. Now on always write back it dips to 15 for some reason, but then quickly goes back up to 450 and maintains it.

While I read there’s some risk to this, it’s just a media server. What I want to be clear on (I’m sure this sounds silly, but… not my specialty here) is that the risk is confined to just some small subset of recent files that are in the cache if there’s a power issue, it won’t impact everything on the drive. Is that the case? If so, how much stays in the cache? How frequently does it get written to the drive from the cache? I’m just trying to get a sense of what’s at risk cause if it’s just some recent files I’m not too concerned and can replace them.

Thanks for the help!