Data transfer slow

[bkwq]

Hello, can anyone please explain or help me with an issue.

 

Data transfer to or from my array is 30-50MB/sec.  Is this normal?  If so, why is it so slow?

 

Thank you.

[Frank1940]

What size files are you transferring?    With small files, the file overhead (which is occurring on both ends of the transfer) is a substantial part of the time required for transfer.  Your speeds are about what I see when doing my monthly data backup from my Win10 computers.

[bkwq]

Thanks for the reply.

 

Larger files 1-2GB over SMB to and from Windows 10.  So this is the norm?  

[Frank1940]

I get about 100MB/s for 20Gb BluRay ISO's and about 80MB/s for 4GB DVD ISO's using a SSD (It is not the fastest SSD on the planet) for a cache drive.   But I am usually doing other things are the same time on the WIN10 computer.  Remember that the copy process in WIN10 is intended to be a background operation and has a very low priority level on resources.  (Remember that the initial design concept for Unraid was that it was to be an archival storage for media and data.  Transfer speed was never one of its design objectives!)

 

You can google using   lan speed   as a search parameter and find some free tools that measure transfer speeds under more controlled conditions.  Remember to test between WIN10 computers if you can for comparison.

[Hoopster]

6 hours ago, bkwq said:

Data transfer to or from my array is 30-50MB/sec.  Is this normal?

The "normal" write speed in a parity-protected array is generally quoted in the 40-60 MB/s range, so, your speeds are not far off "normal."

 

There is a lot of disk reading and writing overhead involved in writing data and in calculating and writing parity blocks.

 

There are several ways to make this faster.

 

1.  Use an SSD cache disk or pool.  This does not actually make the parity calc/writing process faster, it just speeds up getting data to your array by first writing it to an SSD with no parity as a first step.  Later, according to a schedule you set, the Mover process runs to move the data from the cache drive/pool to the array and parity calc/writes take place at that time (2am for example when the array in not likely in use for anything else).  Use of a cache drive/pool is determined by user share settings and can be enabled for some shares and disabled for others.

 

2.  Enable Turbo Write.  Using Turbo Write, many user have reported write speeds in the 80-100 MB/s range.  Turbo write does require that all data drives be spun up all the time.  See the link for details on how this works.

 

3. Use the Auto Turbo Write Plugin.  This plugin enables or disables Turbo Write as needed on demand.

 

Of course, a lot goes into determining how fast data can be written to the array such as, file size and number of files, other activity on the server or LAN, where on the array disks data is being written and the platter rotations required, disk speed and health, operating system considerations, etc.

 

Edited June 8, 2020 by Hoopster

[bkwq]

I tested the transfer speeds over wired connection and got full 110MB/sec read and write.  I should of done this from the start, please forgive my ignorance.