[SOLVED] 6.5.3 - Slow Writes to Cache Drive Over Network

[vorel]

Hi all,

 

I am experiencing slower than expected writes to my Cache drive. Here is my setup:

 

Unraid Server

Version:  Unraid 6.5.3

Cache Drive: 1 X Crucial MX500 1TB 3D NAND SATA M.2

 

Network

• Gigabit NIC on motherboard
• Gigabit switch
• 802.11ac (with macOS reporting 1170 Mbps of Wifi "Tx Rate")

 

My Problem

• When I try to transfer a file, I get about 18 MB/s (see "1-TransferRate.png" attached)

 

Expected Results

• According to the Amazon data, I should expect "Sequential reads/writes up to 560/510 MB/s and random reads/writes up to 95k/90k on all file types". I was hoping to get something at least in the ~100 MB/s range

 

My attempts so far

• I attempted enabling "DirectIO" by configuring "Settings -> Global Share Settings" to "Yes"
• I have my "Test" share set to use Cache Disk as "Only" (see "2-CacheShare" attached)
• I performed the transfer test with all VMs and Docker containers powered off, but I still had the same transfer results

 

None of my attempts have seemed to improve the transfer speed. Does anyone have any thoughts?

 

Edited September 6, 2018 by vorel

[John_M]

12 minutes ago, vorel said:

802.11ac (with macOS reporting 1170 Mbps of Wifi "Tx Rate")

 

Do your tests using a cabled connection.

 

 

[vorel]

Thanks @John_M! So I tested with a WIRED Windows 10 machine and I have much better results (attached). I ordered a "USB-C -> Gigabit adapter" so I can test with my Mac (to make sure it isn't a macOS issue).

 

So far this looks promising, but I am still confused on why wired would be faster (since my wireless is faster than Gigabit and I also have good signal).

 

I will post my results once the new adapter arrives for my Macbook.

[JorgeB]

3 hours ago, vorel said:

since my wireless is faster than Gigabit and I also have good signal

Unlike wired you'll never get nowhere near the link speed on a wireless connection, if you half that it's usually very good, wireless is good for phones and tablets, not much else.

[vorel]

So this definitely is a wired vs wireless issue. For people who are interested why, it is quite easy for there to be some confusion.

 

Although I have 1300 Mbps throughput, my wireless connection is "half duplex". This means only one person can talk at a time (like a walkie-talkie) I have high-end WiFi equipment, but consumer devices are still half duplex.

 

Gigabit connection is "Full duplex". This means the throughput is slower, but is bidirectional. This makes it extremely fast compared to wireless (especially in TCP connections).

 

Wow, today I learned a lot 😀Hope this helps!

 

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