I have a medium sized file storage website that allows people to backup their data online. A lot of these files are shared, and receive large amounts of traffic. I have several types of servers, and I have yet to find the "sweet spot" where I could utilize most of the hard drive space, without it hitting IO limits of the drives.
The most capable server that I have is 8 x 128Gb SSDs in raid5 4K blocks. Its peaks out at around 320MB/s of random reads, and it looks like it still has some room to push more. Then I have a 3 x 300GB 15k SAS raid0 box, that could barely do 45MB/s before it hit its io limit, and load skyrocketed.
When I look at various drive benchmarks, I see most modern SSDs can do ~ 50MB/s of random reads. Does that mean it scales more or less linearly? So if I had 12 of these in raid0, I could do around 600MB/s of random reads? How badly does raid5 decrease the performance?
Also I heard TRIM becomes disabled if RAID is used, so performance would degrade faster. I that true?