Low write speeds

[DigitalLF]

Regarding WD Red

 

My unRAID consists of 4 WD Red two are PARITY and two are DATA.

and one WD Red mounted with "Unassigned Devices"

 

I have a server with ESXi and on that i run (pfSense,) Win Server 2016, unRAID and yesterday i had a WD Red 8Tb that i moved everything of it to my unRAID and i wore transferring at around 175mb/s and now i wanted to do it again but from a new WD Red 8 Tb but this time at first I tried to move it from my VM Win Server 2016 and i only got 50mb/s and today i moved the physical drive over to my HBA card (PCI pass through to unRAID) where the information was going because i found "Unassigned Devices" and i still only get 50mb/s so there must be some setting i missed or changed or something.

 

Anyone here know what could be the reason for the slow speed?

[JorgeB]

That's about normal for default writing mode, try with turbo write:

 

 

[DigitalLF]

1 hour ago, johnnie.black said:

That's about normal for default writing mode, try with turbo write:

 

 

 

Then why did i have 175mb/s yesterday? i did not enable Turbo Write. weird.

 

now i have tried Turbo Write. it did not help. i still get 60 MB/s

[JorgeB]

11 minutes ago, DigitalLF said:

Then why did i have 175mb/s yesterday?

That's an impossible sustained write speed without turbo write, unless you only had one data disk.

[DigitalLF]

8 minutes ago, johnnie.black said:

That's an impossible sustained write speed without turbo write, unless you only had one data disk.

 

Darn it. Yesterday i only had one DATA drive.

 

The disk i cleared yesterday has been added as a DATA drive to the array. So right now i have two DATA drives and i'm now moving the information from a NTFS drive that i mounted and the information is now getting moved to the array and after that i will expand with that drive as a DATA drive.

 

 

Thank you for explaining it for me!

[JorgeB]

That explains the much better performance yesterday, with only one data disk unRAID works like a raid1 array, so no parity read/write/modify, still with turbo write enable you should get similar performance, as long as there are no hardware bottlenecks, the disadvantage is that all disks will spin up for writes.

[DigitalLF]

7 hours ago, johnnie.black said:

That explains the much better performance yesterday, with only one data disk unRAID works like a raid1 array, so no parity read/write/modify, still with turbo write enable you should get similar performance, as long as there are no hardware bottlenecks, the disadvantage is that all disks will spin up for writes.

 

The HBA i got is a Supermicro based on LSI 3008 and it has SAS3 so that won't be the bottleneck. i just would have liked it to be really fast when I'm rebuilding and moving the information i could just switch back after that.

 

i checked in unRAID and it seems like i'm only using about 30% of what i gave that VM.

[JorgeB]

This is one of my servers,  with 7 x 8TB Seagate archive drives and turbo write enable:

 

[DigitalLF]

I really don't know why then. It is just so slow.

 

Here are a few screenshots that might help! reminder!! this is running in a VM in ESXi from a usb drive with PLOP but it has worked.

 

As you can see in the first picture right now I'm adding one disk so and NOT transferring anything. Avg. CPU usage is 4% and mem usage is 49%

 

 

[JorgeB]

I never virtualized unRAID, maybe there's a performance hit.

[JorgeB]

Also, test again after the disk finishes clearing, though not part of the array yet unRAID doesn't really perform well when doing simultaneous I/O.

[DigitalLF]

1 hour ago, johnnie.black said:

Also, test again after the disk finishes clearing, though not part of the array yet unRAID doesn't really perform well when doing simultaneous I/O.

 

i did try it before i added the last drive. it was the same.