So first of all, I'm new here - so "Hi". Secondly, thanks to the unRAID team for an amazing OS!
I did try to search for this but couldn't find anything immediately on the forums so thought I'd start this thread hoping to get some advice from the community.
Currently, I have a mixed array of disks on my primary unRAID server made up of various rotational speeds, caches, manufacturers etc. What I wanted to know is, I am starting to approach a point where I will soon need to start investing in newer, higher capacity drives to expand my storage.
So, my question/what I'm looking to find out is this:
Is there a recommended method of provisioning drives in an unRAID server to optimize the performance of the system?
In other words, I'm trying to work out things like:
* Should one try to provision the same model drives in the array?
* How much does the onboard drive cache matter in an array?
* Is performance impacted if drives vary in their cache amounts?
* Does the rotational speed of the drives matter?
* Should the parity disk be a higher performance drive compared to the storage drives in the array?
Reason I'm asking is because I have noticed that in some cases, a copy operation to my server often will hit speeds of just over 100 MB/s from a networked machine, but then if it's a particularly large copy, at some point it starts slowing down to a crawl at times even appearing to pause before resuming.
Monitoring disk activity it would seem that the parity drive appears to be grinding hard to write parity, while the storage drives in the array often appear to be waiting for the parity disk to catch up. It got me wondering about the relationship between the disk performance of the parity drive vs. the storage drives, and as the number of storage drives increase, how that has an impact on overall array performance if there is only 1 parity drive.
Any advice is welcome!
Thanks!