11
The Niquist rate says that the maximum rate of independent symbols (fp) is twice the frequency bandwidth of the channel (B).
fp ≤ 2B
Hartly's law introduces the idea that the amount of information that can be encoded in each indepenent symbol depends on the number of different levels that the receiver can distinguish and hence the information rate depends on ...
11
In short:
100BASE-TX (100 Mbit/s) and 1000BASE-T (1 Gbit/s) require category 5 ("100 MHz").
10GBASE-T (10 Gbit/s) requires Category 6A ("500 MHz").
"Smartrate" 2.5GBASE-T and 5GBASE-T work with Category 5, 6 ("250 MHz"), or 6A with varying reach.
To add to the confusion, there's an old Category 5 that was augmented ...
7
I understand your confusion.
The source of that is that some standards originate from the fields of electrical engineering and others from signal processing and network engineering, each with their own conventions and history.
In layman’s terms: The lowest common denominator in the series of network switch on one end , cable in the middle, network card or ...
6
Anything that is of a specification suitable for link speed, link length, and the environment it is used in, and meets that specification(!), should be absolutely fine.
There are basically, practically only four "states" on a wired ethernet connection:
It's working flawlessly, and everything is in the specification (cable types, length...). All ...
4
Since the price difference between 15 ft of Cat5e and Cat6 is negligible I would just go with Cat6 by default these days. There's no good reason not to.
Also note that there's Cat6 shielded and unshielded - don't worry about shielded, that's for 10Gb+ networks, requires shielded connectors, etc, you won't need it.
Given some Ethernet switch
"Some"...
3
What really counts is how you organize your files.
If you plan to have a single big directory with ~10M files any filesystem will suffer, albeit XFS and ZFS will manage even this worst case quite well.
The recommended approach is to organize your files in multiple, smaller directories, with reasonable file counts (~32K) to avoid different but related issues (...
2
Specific to the "Hertz" vs Mbps/Gbps rate part of the question:
Unless you are designing a switch, accessory, or cable stock at the electrical engineering level, or tasked with making a system run outside of specification (eg with longer hauls than the spec allows or on lower-rated cable plant), hertz and decibels (there's a lot of decibel numbers ...
2
From what you describe XFS is a proper match. It was created to handle billions of files. You’ll have to think about right back-end storage for what you plan though.
2
Your work load is almost the worst possible for a general purpose file system. Millions of files, frequent enumeration, lots of reads and writes. Enormous metadata I/O. With large number of files, it rarely the bandwidth of transferring the file themselves that is the problem, rather the number of IOPS to query directory entries and inodes repeatedly.
Test ...
1
Choose the VM option. Be sure you have a fast SSD and enough RAM for all services. 2 VM's should do the trick. Use all cores for VM's and dynamic memory.
1
Unless your server applications are very latency or throughput sensitive, there's no significant loss of performance on modern hardware.
Since you don't tailor a server system to run at 100% capacity but leave (considerable) reserves for future growth, there isn't really too much to think about. If you do need to think about it, calculate 1-5% overhead.
1
Flags [E] and [W] in the tcpdump output are Explicit Congestion Notifications.
When you see theirsite.36652 > mysite.https: Flags [.E] it means that the receiver detected link congestion and asks the sender (your site) to slow down and the sender responds with Flags [.EW] indicating that it acknowledged the request and reduced TCP window.
You can disable ...
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