Confused about Hard Drive Tuning Settings, no info

[Hexenhammer]

Hello,

Before posting I searched the topic and found a LOT of old Information with settings that no longer exposed to user and a 2020 post by some mod that says they no longer necessary and can harm the speed.

 

But the latest unraid version has new settings and no information what they do and how to configure them

If soemone can replay ill apriciate

 

My config is ten 14tb drives, 2 16tb parity [not connected yet], and some SSDs, 32gb of RAM and i have 16gb swapfile enabled on optane SSD to help the CacheDir plugin if it ever needs more RAM.

 

Tunable (enable NCQ): How to Force it to Yes, instead of Auto

Tunable (nr_requests): ?

Tunable (scheduler): 4 Options but no info what each does and which one is suited for what config?

Tunable (md_num_stripes): The only old setting that i found info about but back than in 2016 it also had 2 other settings set with it, and we have just this one. How to set this number and based on what? RAM?

Tunable (md_queue_limit): ?

Tunable (md_sync_limit): ?

 

Thank in advance

[MAM59]

3 hours ago, Hexenhammer said:

Tunable (enable NCQ): How to Force it to Yes, instead of Auto

"YES" is not good (or available) because there maybe disks, that do not support this feature.

Read "AUTO" as : turn it on if it is available.

 

 

[JorgeB]

3 hours ago, Hexenhammer said:

Tunable (nr_requests): ?

Tunable (scheduler): 4 Options but no info what each does and which one is suited for what config?

Tunable (md_num_stripes): The only old setting that i found info about but back than in 2016 it also had 2 other settings set with it, and we have just this one. How to set this number and based on what? RAM?

Tunable (md_queue_limit): ?

Tunable (md_sync_limit): ?

Suggest leaving them all as default, since the changes those settings should not make much difference, unless you go to extreme values but likely in that case it would degrade performance, Unraid basically auto tunes those, except for the scheduler, for for general storage I didn't find much difference changing that, but you can try for yourself if you want.

[Hexenhammer]

20 hours ago, MAM59 said:

"YES" is not good (or available) because there maybe disks, that do not support this feature.

Read "AUTO" as : turn it on if it is available.

 

 

 

I hope it detects it properly.

And what modern Disks dont have NCQ? its been a feature for last 20ish years [maybe USB controllers?]

[MAM59]

34 minutes ago, Hexenhammer said:

And what modern Disks dont have NCQ?

ALL "modern" Disks don't have it anymore, if they use the NVMe protocol instead.

NCQ was limited to 255 commands max, NVMe gets rid of this limit.

 

Anyway, I go with JorgeB: Don't play around with these values, it is unlikely that you are doing something good with it. Maybe you need them someday if a disk freaks out and needs some kick, but normally the defaults are doing well.

 

More Info: NCQ does not make much sense for Flash based drives. It just gives a "slow" disk that needs endless time for stepping to the correct track the chance to sort the ongoing commands to optimize the needed steps to get there. Flash disk dont waste time for stepping.

Edited December 24, 2022 by MAM59

[Hexenhammer]

14 minutes ago, MAM59 said:

ALL "modern" Disks don't have it anymore, if they use the NVMe protocol instead.

NCQ was limited to 255 commands max, NVMe gets rid of this limit.

 

Anyway, I go with JorgeB: Don't play around with these values, it is unlikely that you are doing something good with it. Maybe you need them someday if a disk freaks out and needs some kick, but normally the defaults are doing well.

 

More Info: NCQ does not make much sense for Flash based drives. It just gives a "slow" disk that needs endless time for stepping to the correct track the chance to sort the ongoing commands to optimize the needed steps to get there. Flash disk dont waste time for stepping.

 

All SATA storage does, including SSD [just checked on the ones i have 4Tb Samsung's and they support NCQ]

What is interesting to know if unRAID detects an NVMe device will it disable NCQ globally? That will suck and ill have to remove the single NVme from that PC

 

BTW do you know how to install linux nvme format on unraid?

I have some NVMe drives on windows they all run in emulated 512bytes mode [all commercial nvmes do], but you can change them to 4k and get 10% boost.

on my Segate hard drives i did the same before building unraid, but i did on windows using seagate provided utility, it boosted the speed of my HDDs, some benchmark at 290Mb/s, before never above 265Mb/s [whats strange is that i have identical HDD's Seagate Exos x16, 14TB and couple 16Tb, and they benchmark between 245mb/s lowest to 290Mb/s highest, they all have power management features turned off and all have 4K enabled so why such speed difference between identical drives?]

 

To change NVMe from emulating 512bytes to 4K, you need nvme command on linux

The guide says to install it with this command

sudo apt install nvme-cli

I tried it on unraid, doesn't work, it has no sudo apt command

Any ideas how it can be done, i dont want to create a separate ubuntu flash just to format the SSD's

 

[MAM59]

4 minutes ago, Hexenhammer said:

All SATA storage does,

Yeah, maybe all SATA do now (the command was invented for SATA), but you have talked about "modern" drives and SATA is going down now.

5 minutes ago, Hexenhammer said:

BTW do you know how to install linux nvme format on unraid?

No sorry, And I hardly doubt that NVMe gets a 10% boost from a different sector size (there is no "emulation" because there are also no real sectors anymore).

 

the "sudo" command is not needed on unraid because you are always root already. but I dont know if there is a package nvme-cli. Even if it exists, if you would install it that way it would be gone after the next reboot. Unraid only runs within a RAM disk, local changes are not preserved. You may install a plugin called "community applications" or something like "nerd.." (dunno, the old nerdtools have been canceled, but I guess there is a new one but I dont know the name) and scroll to their offers in the hope to find it there.

 

[Hexenhammer]

14 hours ago, MAM59 said:

Yeah, maybe all SATA do now (the command was invented for SATA), but you have talked about "modern" drives and SATA is going down now.

No sorry, And I hardly doubt that NVMe gets a 10% boost from a different sector size (there is no "emulation" because there are also no real sectors anymore).

 

the "sudo" command is not needed on unraid because you are always root already. but I dont know if there is a package nvme-cli. Even if it exists, if you would install it that way it would be gone after the next reboot. Unraid only runs within a RAM disk, local changes are not preserved. You may install a plugin called "community applications" or something like "nerd.." (dunno, the old nerdtools have been canceled, but I guess there is a new one but I dont know the name) and scroll to their offers in the hope to find it there.

 

This article mentions 10% boost

https://www.bjonnh.net/article/20210721_nvme4k/

 

BTW, I use a software called Hard Disk sentinel on windows

And it shows NVMe device info, and at the bottom of the list there is this:

LBA Format List (Disk Performance😞 512 (Good), 4096 (Better)

 

I guess ill have to make Ubuntu USB