Hi all,

 

as mentioned above I am struggling with low write performance to my cache SSD over Lan.

everything else is running perfectly, my download speed from the share is approx 100MB/s (I have no idea on how to get the speed test apart from copying to and downloading from, any suggestion on alternate method is appreciated) 

 

• xeon e3-1220 v3
• 16gb DDR3 Ram
• 1x 3t HDD
• 1x 120 SSD for cache,

 

dianostic file is attaced, Any idea? 

 

 

samsbay-diagnostics-20200826-1116.zip

Is the speed better if you copy directly to the array?

You could try with "DiskSpeed" from CommunityApp or dd command (https://www.cyberciti.biz/faq/howto-linux-unix-test-disk-performance-with-dd-command/)

Also test transfer speeds with very large files > 20GB in your case.   File overhead can be a problem even with using ssd's.  (Your CPU is not exactly a barn burner these days.)  You have 16GB of memory and it looks like you might have a considerable of RAM available as a cache for writes.  You should really be seeing a initial burst of write speeds at the 100(+)MB/s rate and then a dropback after the RAM cache fills up. 

12 hours ago, johnnie.black said:

Is the speed better if you copy directly to the array?

if cache is not enable, i getting a jummpy speed from 30-60MB up and down,

8 hours ago, Frank1940 said:

Also test transfer speeds with very large files > 20GB in your case.   File overhead can be a problem even with using ssd's.  (Your CPU is not exactly a barn burner these days.)  You have 16GB of memory and it looks like you might have a considerable of RAM available as a cache for writes.  You should really be seeing a initial burst of write speeds at the 100(+)MB/s rate and then a dropback after the RAM cache fills up. 

i was using a 8gib movie to do the testing, i did wonder replacing the CPU would help, but didnt see CPU usage ramp up that much when i was copying the file.

12 hours ago, Iker said:

You could try with "DiskSpeed" from CommunityApp or dd command (https://www.cyberciti.biz/faq/howto-linux-unix-test-disk-performance-with-dd-command/)

try to do brenchmarking on the drive?

10 hours ago, iamsammajor said:

if cache is not enable, i getting a jummpy speed from 30-60MB up and down,

That suggests a network or source problem, without parity you should be able to write to the array faster than that, start by running iperf.

13 hours ago, johnnie.black said:

That suggests a network or source problem, without parity you should be able to write to the array faster than that, start by running iperf.

i am learning how to run iperf, will report back result. thanks for helping

14 hours ago, johnnie.black said:

That suggests a network or source problem, without parity you should be able to write to the array faster than that, start by running iperf.

i have this result.

Close enough, do you have another source computer you can test the transfer with?

On 8/28/2020 at 6:53 PM, johnnie.black said:

Close enough, do you have another source computer you can test the transfer with?

I borrow my friend’s laptop. It’s iperf result is close and do have the write speed of 110MB/s. I tried update the nic driver but didn’t make any difference. 
it is isolated to my pc end but I’m not too sure what else can be done.

At least you now know where the problem is, if you can try a different NIC on the PC, it can also be an OS issue, re-install might help.

Be sure you swap to a different port on the switch that the PC is connected to .   You should also power cycle the switch.  These things all have a SOC chip in them and a reboot often clear problems.

Edited August 30, 20205 yr by Frank1940

8 hours ago, johnnie.black said:

At least you now know where the problem is, if you can try a different NIC on the PC, it can also be an OS issue, re-install might help.

 

8 hours ago, Frank1940 said:

Be sure you swap to a different port on the switch that the PC is connected to .   You should also power cycle the switch.  These things all have a SOC chip in them and a reboot often clear problems.

 will try both, and keep you guys posted, thanks for your help