Slow Write to SSD Cache Drive

[driftking]

Hello,

 

I am not sure where to start looking for an issue with the slow write speed to the SSD Cache drive.  I am pretty sure nothing drastic has changed with the system or network so i'm kinda stumped at the slow speeds.

 

In the past and since the beginning of the SSD cache drive, I would almost max the gigabit transfer speed at 120MB/s.  But now I am lucky to get 80MB/s and average around 50MB/s with my last write transfer sitting at 35MB/s.

 

If anyone has any ideas or needs further info please let me know.

 

M/B: ASUSTeK Computer INC. - P8Z68-V LX

CPU: Intel® Core™ i3-2100 CPU @ 3.10GHz

Memory: 8192 MB (max. installable capacity 32 GB)

Network: eth0: 1000Mb/s - Full Duplex

Kernel: Linux 4.1.5-unRAID x86_64

 

2 x Supermicro AOC-SAS2LP-MV8 (Party Disk + Data Disk 1-9 are plugged into SAS)

1 x SSD Cache drive plugged into motherboard SATA3 port.

[JorgeB]

Do you TRIM it regularly? Not doing it can cause slower wrights.

[danioj]

Do you TRIM it regularly? Not doing it can cause slower wrights.

 

If johnnies.black is right about your issue and you need to start using TRIM on your SSD Cache drive then the following "SSD TRIM" Plugin from Dynamix works nicely AND you get to schedule when it runs from the GUI! 

 

http://lime-technology.com/forum/index.php?topic=36543.0

 

Note that it works on any SSD drives in your cache pool (if using one) as well as if you're running a single SSD cache drive. Note that at the time of posting the Plugin only works on SSD's that are being used as cache and not any mounted via other means (e.g. Unassigned Devices Plugin).

[dvd.collector]

I had a similar issue with my ssd cache drive.  Initially transferring to it via my win8.1 desktop i was seeing >100MB/s speeds.  However at some point over a period of months, this dropped to max out at around 60MB/s.

 

I couldn't work out what was causing it, so ended up assuming it was the SSD which had slowed over time.

 

However having recently wiped my desktop and put win10 on it, I'm back to writing at 120MB/s to the cache!  I can't explain why this would be, but it does seem it was something to do with my desktop.  I wondered if it was related to network drivers or something, as on win10 i've just left everything as win10 installed it - whereas on my older setup i had installed specific intel drivers from their website. 

 

 

[driftking]

i have not been running TRIM on the SSD.  I have installed the plugin as you suggested.  Thanks for the easy link to the forum thread.  I have setup the scheduler to trim daily.  I will see if things improve from here.

 

I will have to find another device to hardwire into the network to try the transfer speeds to the unraid server.  This should help narrow it down to my desktop PC or unraid server causing the issue.