G+_610GARAGE Posted December 11, 2015 Share Posted December 11, 2015 SAS or sata drives for nas? I recently had a very traumatic experience. The raid card in my vm server at work died causing 2 days of down time. =( To make sure that doesn't happen again, I got another server, and I am going to set up the two servers in a vm pool. But In order to do that effectively, I need to set up shared storage on my freenas box, which means more drives. Since I need these drives to be somewhat fast to reduce lag, I was wondering if it would be worth getting sas drives. There only $30 dollars more that wd red pros. But my sas backplane is only 3gb/s (though my hba is 6gb/s). And there still spinning drives. So is there any benefit? If there is, any recomendations? Link to comment Share on other sites More sharing options...
G+_Taylor Graham Posted December 11, 2015 Share Posted December 11, 2015 SAS is the only way to go if you want enterprise grade stuff. Also, if seek time is an issue, make sure you go with 10k or 15k rpm drives. SAS drives are way more reliable than consumer sata drives. That should help a lot. Your backplane should just be the physical sas connectors, if your raid card supports 6gb/s, thats what you should get (right?). Let me know how freenas performs with 10k or 15k drives if you go that route. I love my freenas but on 7200rpm drives, it definitely has seek time issues. Link to comment Share on other sites More sharing options...
G+_610GARAGE Posted December 11, 2015 Author Share Posted December 11, 2015 Taylor Graham I'm very confused about backplane speeds. There is a chip on the backplane that the signal goes through. So I don't know if it just switches drives, or if it actually relays the signal to the drive. Eeek, those 10k drives are pricey. I think I would have to stick with the 7200 drives. Link to comment Share on other sites More sharing options...
G+_Taylor Graham Posted December 11, 2015 Share Posted December 11, 2015 I'm not 100% sure myself. But do you even need 6gb/s? If you aren't putting in ssd's, that shouldn't be a bottleneck. That's 400 MB/s or so in available throughput, maybe a bit less in the real world. Yep, speed and reliability are pricey unfortunately. I could never bring myself to buy 10k drives unless i was billing someone for them. You could try to use an SSD for caching. I haven't done it myself but if i remember correctly, it's a feature in freenas. That should help speed things up. Link to comment Share on other sites More sharing options...
G+_610GARAGE Posted December 12, 2015 Author Share Posted December 12, 2015 Taylor Graham That's the other thing about sas that confuses me. With sata, you have 6gb/s to each drive (assuming your southbridge isn't a bottleneck). But with sas,is it 6gb/s per cable? If so, then yea, 6gb/s would be nice because I would assume that the hba could talk to more drives in less time. But I kinda doubt that it would be 6gb/s per cable, but rather 6gb/s per channel. Which would mean that I really don't need 6gb/s. Basicly, I'm very confused over sas. :) A ssd cache would be interesting. There's a lot of random read/writes, so I am not too sure how effective that would be. But it would be intriguing to find out. Link to comment Share on other sites More sharing options...
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