LAN speed
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So we need to figure out if the speed issue exists from the sending point, the receiving point or along the path.
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You would not expect to be getting 1Gb/s in any way from even a perfect NAS able to stream from memory. With Ethernet, TCP/IP and iSCSI overhead alone you'd normally max out around 800Mb/s and with NFS or SMB a little lower than that. That's if perfect.
Typically storage is measured in IOPS, not in through (bandwidth) because this is what matters nearly all of the time. Throughput does matter, but isn't what generally impacts us. You almost never see storage requirements written in anything but IOPS. This is because of how storage happens... the delays and performance issues almost always come from an inability to "do different things" rather than to stream data on or off. If you plan to use this as a streaming media server, that could be different, but for normal use, throughput isn't a real concern.
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In order to measure throughput in any real way you need a single, extremely large file that will transfer for twenty minutes or so and a receiving unit that has "unlimited" ability to accept the file (preferably into memory, not disk) and a network that you know has no saturation (this could be a quiet switch, a switch with nothing but this connection or a crossover cable.) Eliminate the "noise" and things that cause interruptions so that you can, as clearly as possible, look only at the throughput.
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Scott - what tool would you use to create a 120 GB file to keep a 1 Gb link saturated for 20 mins (assuming 800 Mb/s transfer)?
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@scottalanmiller said:
@IT-ADMIN said:
@DustinB3403 said:
Can you go into the network page on the NAS, and screen shot that for us?
I have a feeling the speed within the NAS is set to Auto. Which if it is, is likely causing the performance of the NIC to be slow. So either there is something wrong with the configuration on your Switch. Or the NAS.
yes you are right, the link speed is set to auto, should i change it to 1000 ??
No, it is working perfectly now. GigE requires Auto. Setting it to 1000 is an unofficial mode only supported by a few vendors who don't follow the specs.
Now that you say that - I do recall something about Auto being the standard - Is that in an RFC?
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now the speed is 24.2 MB/s
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Well you're at 201 Mb/s now - what protocol are you using? SMB 2.0/3.0?
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maybe if i change it to SMB 3.0 i will get more speed
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???
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@Dashrender said:
Scott - what tool would you use to create a 120 GB file to keep a 1 Gb link saturated for 20 mins (assuming 800 Mb/s transfer)?
dd will do that, if you are on the NAS CLI.
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@Dashrender said:
@scottalanmiller said:
@IT-ADMIN said:
@DustinB3403 said:
Can you go into the network page on the NAS, and screen shot that for us?
I have a feeling the speed within the NAS is set to Auto. Which if it is, is likely causing the performance of the NIC to be slow. So either there is something wrong with the configuration on your Switch. Or the NAS.
yes you are right, the link speed is set to auto, should i change it to 1000 ??
No, it is working perfectly now. GigE requires Auto. Setting it to 1000 is an unofficial mode only supported by a few vendors who don't follow the specs.
Now that you say that - I do recall something about Auto being the standard - Is that in an RFC?
Yes. The GigE RFC states that only Auto can be used. Cisco uses their own standard that isn't true Ethernet. One of the many reasons I avoid craptastic Cisco gear. Non-standard Ethernet? You've got to be kidding me.
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@IT-ADMIN said:
now the speed is 24.2 MB/s
Awesome. It was probably just small files being used and not getting a chance for the TCP/IP tuning to kick in yet. That shows that you are getting the GigE connection for sure.
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@IT-ADMIN said:
@Dashrender said:
Well you're at 201 Mb/s now - what protocol are you using? SMB 2.0/3.0?
SMB 2.0
SMB is not very efficient. Not like it cuts your throughput by 75% or anything, but you don't use SMB for speed. NFS is quite a bit faster. But this should not be an issue. Sounds like you are getting fine performance.
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@IT-ADMIN said:
maybe if i change it to SMB 3.0 i will get more speed
Likely less. SMB 3 does more, not less.
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@IT-ADMIN said:
now the speed is 24.2 MB/s
Notice here that you are copying 79K items, not a single item. So you are not getting anywhere near the potential throughput unless individual items are many GB in size, then you could only look during those specific items. If that PST is 10GB, for example, you should see it get much, much faster than if you have tons of 4KB files. Each file requires the SMB protocol to set up and tear down the connection. It is not efficient for this kind of access at all.
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@scottalanmiller said:
@Dashrender said:
Scott - what tool would you use to create a 120 GB file to keep a 1 Gb link saturated for 20 mins (assuming 800 Mb/s transfer)?
dd will do that, if you are on the NAS CLI.
dd in=/dev/zero of=zero.txt bs=4k count=400000
Pay attention to the output when it finished. It will also give you some information on how fast it wrote zeros to the drives. You can then use zero.txt to transfer to different points on the network.
Don't forget to delete that file when you're finished, it's literally 1GB of zeros.
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Set up ftp server on that NAS and try to transfer a few big files. Hardly anything comes close to ftp in terms of raw speed.
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@travisdh1 said:
@scottalanmiller said:
@Dashrender said:
Scott - what tool would you use to create a 120 GB file to keep a 1 Gb link saturated for 20 mins (assuming 800 Mb/s transfer)?
dd will do that, if you are on the NAS CLI.
dd in=/dev/zero of=zero.txt bs=4k count=400000
Pay attention to the output when it finished. It will also give you some information on how fast it wrote zeros to the drives. You can then use zero.txt to transfer to different points on the network.
Don't forget to delete that file when you're finished, it's literally 1GB of zeros.
For testing, try it with /dev/random instead of /dev/zero. Using all zeros can be misleading as things can compress it like crazy and show super high transfer rates when nothing is being transferred.
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@marcinozga said:
Set up ftp server on that NAS and try to transfer a few big files. Hardly anything comes close to ftp in terms of raw speed.
Still needs those "few big items" though.
