March 12, 201412 yr No matter what I do, recently I cannot break 75MB/s on gigabit to my server. When transfering 75MB/s to the cache drive, the server is also very slow to access even from other devices.. making me believe that it's not getting full gigabit. Is there anyway to verify this, and make sure it's not just the hard drive? Specs below.
March 13, 201412 yr Yes. 75Meg to the cache sounds like the constraint is the speed of the cache drive, not the network. There's nothing practical that can be done to make the platters spin faster... I can't find the thread, but I seem to recall that a SSD cache drive only goes ~150 Meg. What are you using as your cache drive? Rotating or SSD?
March 13, 201412 yr Author An empty 3TB black cache drive is capable of faster than 75MB/s though... Around 145MB/s according to tests. If the limit was not the network, then why does access to the server slow down to a crawl while xfering to the cache drive? I'm accessing entirely different disks, and even file browsing is very slow. It would still would have ~25MB/s of bandwidth and shouldn't slow down access to the server at all if the HD was the limit.
March 13, 201412 yr An empty 3TB black cache drive is capable of ...145MB/s according to tests. Notwithstanding the capabilities of your drives, the theoretical max speed for a Gb connection is 125MB/s ... and realistically you're not likely to get more than 115-120GB. I've seen 120GB/s, but typically get around 116-117GB/s transfers FROM the array to another PC. But you're correct, however, that you should see speeds better than 75MB/s on a WD Black. Are these just write speeds -- or is it just as slow when you're reading from it? And are you CERTAIN that your external source/destination is capable of transfers faster than 75MB/s ??
March 13, 201412 yr Author An empty 3TB black cache drive is capable of ...145MB/s according to tests. Notwithstanding the capabilities of your drives, the theoretical max speed for a Gb connection is 125MB/s ... and realistically you're not likely to get more than 115-120GB. I've seen 120GB/s, but typically get around 116-117GB/s transfers FROM the array to another PC. But you're correct, however, that you should see speeds better than 75MB/s on a WD Black. Are these just write speeds -- or is it just as slow when you're reading from it? And are you CERTAIN that your external source/destination is capable of transfers faster than 75MB/s ?? I enabled jumbo frames on the source computer and the server, and i'm now seeing peaks of 111MB/s. This is close enough for me, strange though.
March 13, 201412 yr Sounds good ... I believe mine are all set for jumbo frames as well (been awhile since I've set all that up).
March 13, 201412 yr An empty 3TB black cache drive is capable of ...145MB/s according to tests. Notwithstanding the capabilities of your drives, the theoretical max speed for a Gb connection is 125MB/s ... and realistically you're not likely to get more than 115-120GB. I've seen 120GB/s, but typically get around 116-117GB/s transfers FROM the array to another PC. But you're correct, however, that you should see speeds better than 75MB/s on a WD Black. Are these just write speeds -- or is it just as slow when you're reading from it? And are you CERTAIN that your external source/destination is capable of transfers faster than 75MB/s ?? I enabled jumbo frames on the source computer and the server, and i'm now seeing peaks of 111MB/s. This is close enough for me, strange though. How do you enable jumbo frames (or at least verify they are enabled) in Unraid (4.7)?
March 13, 201412 yr How do you enable jumbo frames (or at least verify they are enabled) in Unraid (4.7)? http://bit.ly/1cX5eRe
March 13, 201412 yr Do you have to change all other devices to 9000 as well? If all devices aren't using the same MTU I believe the end result is packet fragmentation, which has a negative impact on network performance.
March 13, 201412 yr Do you have to change all other devices to 9000 as well? If all devices aren't using the same MTU I believe the end result is packet fragmentation, which has a negative impact on network performance. That sounds right...my ISP supports Jumbo frames, so I set it up on my router and then my Mac..and then discovered that wife's Mac had to be changed, and then I realized that my smart phone, tablet, ROKU, etc., would need to be changed. And then I decided that it wasn't worth it. There's probably some way to do this without disrupting the entire house (subnets, or some such), but I've come to prefer 'simpler' over 'faster'.
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