Hello all.
Completely new to the Unraid experience. I've recently decided to build a new server and managed to get some nice hardware that a company was no longer using. Everything seems to be going fine, but I am seeing some very slow parity speeds and can't seem to figure out what is going on. I have trawled through these forums and absorbed a massive amount of data, it really helped me get my system off the ground. Been lurking and learning ever since, but I seem to have hit a roadblock.
I've got 8 1TB WD Red 2.5" drives in my array, and 2 2TB WD Blue 2.5" drives as parity (the gear I have only supports 2.5" drives via a Dell PERC H730P card running in HBA mode). All drives are less than two weeks old and individually run at good speeds. When the parity job starts, it looks great, over 100MB/s and an estimated process time of 6ish hours.
Within 20-30 mins though, the speed slows to a crawl and the estimated time goes from hours to days. I've tried stopping, rebooting, and kicking off the process again with the same results.
I've set the md_num_stripes tunable to 4096 based on a number of posts in the forum, doesn't seem to have made a difference. I've disabled everything I could find including docker, nothing should be taxing these drives at all apart from the parity build. I know the parity drives are not the best model, but could that explain such terrible performance?
Turbo write is enabled, all other settings are at defaults. I'm also wondering if it's the PERC card that is making things difficult, all the other hardware should be resulting in pretty good performance, and it's the only bit of hardware that I am not entirely familiar with. Are there any special settings within Unraid or even the BIOS (Dell Poweredge T630) that I should be paying attention to for it?
One thing to note is that I got the parity drives after I had built the system. I transferred data to the array storage disks before they were installed. Not sure if that makes a difference.
Is anyone able to give me some advice on what I might need to look into? Not quite sure what other details to provide here that would be relevant. I'm planning to add one or two drives to the array every month to expand the storage capacity over time, but am a little worried that it might not be the best investment with this kind of performance.
Any advice on where I could go from here would be fantastic.