Great Improvement in write speed after this... BUT (SOLVED)

[kinaley]

Hello friends,

I the write speed has increased to 100+MB/s after running the command mentioned some where in this forum

The below command will change the value from 0 to 1 and the write speed is great.

sdparm --set=WCE /dev/sdb
sdparm --set=WCE /dev/sdc
sdparm --set=WCE /dev/sdd
sdparm --set=WCE /dev/sde
sdparm --set=WCE /dev/sdf
sdparm --set=WCE /dev/sdg

 

but after reboot the write speed is back to slow i type the below command to check the status

sdparm -g WCE /dev/sdb
sdparm -g WCE /dev/sdc
sdparm -g WCE /dev/sdd
sdparm -g WCE /dev/sde
sdparm -g WCE /dev/sdf
sdparm -g WCE /dev/sdg

and the output displays 0 for all .

I again have to re-run the command to enable

is there a permanent way to fix so that it will work even after reboot ?

is the settings available in BIOS ? I'm on very old server Dell R710, with H200 RAID controller.

Thanks

Edited April 11, 2019 by kinaley
solved

[JorgeB]

You can run the command with the user scripts plugin, schedule it to run at first array start.

 

 

 

 

[trurl]

But note that the /dev/sdX assignments are not guaranteed to be the same after reboot.

[JorgeB]

39 minutes ago, trurl said:

But note that the /dev/sdX assignments are not guaranteed to be the same after reboot.

Good point, though unless the hardware changes and/or more devices are added they should remain the same, and without more devices it will at least use the same letters even if the device order changes.

[kinaley]

15 minutes ago, johnnie.black said:

Good point, though unless the hardware changes and/or more devices are added they should remain the same, and without more devices it will at least use the same letters even if the device order changes.

Well Technically for me it's not problem if sdb changes to sdc and vice versa as long as all has Write Cache or what ever that is enabled.

Ok one quesiton although i have never seen it happening in windows environment. If it were to in windows server then is that change of sdb,sdc,sde like change in drive letter D,E,F,G ?

[JorgeB]

Not really, D,E,F are more like the mount points, in windows disks are assigned numbers as they are detected, you can see them in disk manager, disk 0, disk 1, disk 2, etc.

[trurl]

47 minutes ago, johnnie.black said:

Good point, though unless the hardware changes and/or more devices are added they should remain the same, and without more devices it will at least use the same letters even if the device order changes.

Note that simply attaching unassigned devices might affect this also.

[trurl]

18 minutes ago, johnnie.black said:

Not really, D,E,F are more like the mount points, in windows disks are assigned numbers as they are detected, you can see them in disk manager, disk 0, disk 1, disk 2, etc.

And in Unraid, disks are assigned slot numbers based on their serial numbers. That happens independently from the sdX designations linux gives them. The slot numbers are what you normally will work with. Writing directly to the sdX devices will invalidate parity.

[kinaley]

Thank you johnnie.black, trurl and Constructor.

I'm enlightened.