Hello

 

I have an HP n54l with xpenology and i move the data (and the disks) to my new unRAID, with remote folder (CIFS) from my synology nas

(for a strange reason remote folder on xpenology doesn't work)

 

In the first 3 disks (2 data, 1 parity) i had normal write speeds for an unRAID built, around 30-80mb/s.

When i add the 4 disk (3 data disk) and start to copy, i had normal speeds again, but when i filled it with 4TB of data and  although it starts to copy with 40-60mb/s, after a few minutes (or an hour) it goes down to 3-14mb/s..

 

I know that unRAID have slow write speed but 3-14mb/s i think isn't normal.

 

does the split level or allocation method effects the speeds?

i dont think so, but anyway..

 

thanks in advance!

 

 

 

 

Edited July 18, 20178 yr by volume

One thing that can impact write speeds is transfers with lots of small-size files.  The effective transfer speed is impacted by the file creation and disk space allocation overhead.  Plus, there is a lot more mechanical head movement time associated with this process than with larger files which further impacts effective write speed. 

 

EDIT:  Plus, you are getting to the inner tracks on these disks which also has an impact on write speeds.  It also appears that you are using the WD 8TB disks that were not designed to have the fastest write times to begin with.  As I recall, they were designed with data archiving applications in mind and certain compromises  were made in the design to achieve maximum storage capacity. 

Edited July 18, 20178 yr by Frank1940

12 minutes ago, Frank1940 said:

One thing that can impact write speeds is transfers with lots of small-size files.  The effective transfer speed is impacted by the file creation and disk space allocation overhead.  Plus, there is a lot more mechanical head movement time associated with this process than with larger files which further impacts effective write speed. 

 

EDIT:  Plus, you are getting to the inner tracks on these disks which also has an impact on write speeds.  It also appears that you are using the WD 8TB disks that were not designed to have the fastest write times to begin with.  As I recall, they were designed with data archiving applications in mind and certain compromises  were made in the design to achieve maximum storage capacity. 

 

I have the Seagate Archive 8TB disks, and i mostly copy to unRAID big files of video, right now i have decent speeds around ~40mb/s

so i guess it is normal.

 

it's strange though, that i have slow speeds, only when i add the 4 disk. With the previous 3 disks i never seen speeds below 30mb/s.