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maximum Gigabit saturation?

Western Digital Drives - The Preferred Drives of FreeNAS and TrueNAS CORE
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toyebox

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Aug 20, 2016
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Hey everyone. First off, thanks so much for all the amazing work that has been done here. You guys are amazing. I have just setup my first freenas box, and im very happy. I have a single cat5 cable on a gigabit connection to my gigabit switch. I'm assuming this is my bottleneck because i did some tests and here were the results:

Code:
[root@freenas /mnt/RAID_10]# dd if=/dev/zero of=tmp.dat bs=2048k count=50k     
51200+0 records in                                                             
51200+0 records out                                                             
107374182400 bytes transferred in 24.654287 secs (4355193196 bytes/sec)         
[root@freenas /mnt/RAID_10]# dd of=/dev/zero if=tmp.dat bs=2048k count=50k     
51200+0 records in                                                             
51200+0 records out                                                             
107374182400 bytes transferred in 13.402024 secs (8011788529 bytes/sec)  


Am i reading that correctly? What does that convert to? 445 MB/s write and 800 MB/s read?

What should i see on a single gigabit connection? 120ish?

Thanks in advance!~!
 

MrToddsFriends

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Jan 12, 2015
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Your internal I/O measurements using dd are most likely affected by caching effects. 2048 kBytes * 50 * 1024 = 100 MBytes, which is most likely only a fraction of the size of the RAM of your server.

BTW: You misread the number of digits: 4355193196 bytes/sec equates to 4153 MBytes/sec (not 445).

On a Gigabit network connection (CIFS share) you should be able to see 100+x MBytes/s when transferring a single large file (using appropriate hardware, of course).
 
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toyebox

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Aug 20, 2016
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Thanks so much for the clarification! To be honest i did read the MBytes/sec correct, but figured it couldn't be right :P

So to mitigate the affects of caching, should i try using a larger file?
 

MrToddsFriends

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