Originally Posted by wsume99
I may regret this but would you mind sharing why you are debating this?
It already takes a long time to calculate parity or do "VERIFY" and "VALIDATE" with Flexraid. It basically takes the amount of time it takes to read all your data off all your drives simultaneously. Usually this means for whichever HDD is the slowest or most full. Currently I can get all this done in a nightly update at 2am when I am sleeping and it is done by morning. But I have faster than average 7200rpm Seagate 3TB drives that read and write at good speeds. If I went with a slower 4TB HDD's they read about 30MB/sec slower- which is not a huge deal on it's own. But also would need to read 1TB MORE DATA too. So 30MB/sec slower for a 5400rpm or 5900rpm HDD over an entire 4TB of stuff is going to take longer.
My fear is it might take too long if I go up in size and down in speed.
Just a debate I have with myself.
Since I have a 20 bay Norco server chassis I have enough room for more drives. I already installed two SATA HBA x8 cards and all my 20 bays are hooked up and working. So far I have been able to buy 3TB drives that are faster and still good on energy for $99 each or less ($33 per TB) I even bought a couple at $79 each, and $89 each. I've never been able to buy 4TB as cheap so that's the primary reason I did not do it yet. I have not upgraded my parity to 4TB, it is only 3TB. I can only add up to 3TB without upgrading my parity drive larger at the same time.
If I see an amazing deal on 4TB drives I might upgrade both my parity drives, with 4TB and add one or two more 4TB as data drives. I could also take my current parity drive and make it a data drive and gain even more space.
I just worry about how much longer it might take to do parity updates, or restore a drive. Restoring a full 4TB is going to take a while.
Flexraid and software raid that uses snapshot really works better (best) with more drives that are faster and smaller. This cuts down on the time it takes. The bigger and slower the drive the longer it's going to take. Just how it works.
Bigger isn't always better. More space is better, but bigger drives are not always better. Not from a performance standpoint. A couple fewer drives would save me a couple dollars in electricity though. (I don't really care about a few dollars)