Unusable shares (shfs issue)

[Gigabyte2]

Hi,

I’m running Unraid 6.9.2 and I’m having an issue to upload files to a quite big folder (2000 files). Uploading 1700 files (25GB) takes over 3 hours from Mac.

Top command shows me shfs process with very high CPU usage!!

How can I solve this?

 

Best regards

[Frank1940]

We will need a bit more information about your setup. 

 

Is anything else doing a save operation to the array at the same time?

 

Are you using a cache drive?

 

Are you doing any  type of parity operation? 

 

You should also provide your Diagnostics file.   Tools    >>>   Diagnostics     Upload the file in a new post. 

 

Unraid is capable of doing this in a timely manner.  Once a month, I back up a about 20GB of data in less than a half hour--- >4000 files in more than 500 folders.  I do have a 500GB SSD cache drive.   (I have no idea how long it takes Mover to relocate this backup to the array as it happens at 3:00AM!)

[Gigabyte2]

There is no operation running in the array and mover runs at 3:40am every day.

I'm using cache drive since a month with any problem but yesterday I uploded to a smb share a lot of files inside a single folder, transfer is running since yesterday for less than 50GB...unusable!

Attached the diag file generated now.

gigavault-diagnostics-20211115-0953.zip

Edited November 15, 2021 by Gigabyte2

[Gigabyte2]

I'm noticing that issue occurs during transfer lot of files in a folder with thousand files inside, there are no problems in a single file of few files transfer.

[Frank1940]

You have two cache drives in this system.  Which one are you using for the share that you are having the issue with? 

 

Now for some bad news.  Not all SSD's are equal.  There are several fabrication techniques used to make SSD's.  Some of the  are very fast but they are very expensive on a per bit basis.  Others are very cheap on a per bit basis but their performance suffers.  (Google MCL vs TCL vs SLC)  Some drives that use the slower attempt to 'hide' this fact by using a large block of high speed memory as an on-drive cache but as soon as it is filled things slow down to the basic write speed of the cells used to actually store the data.  (Note this means that this permits such a drive to perform very well as a typical consumer OS/data drive where the writes will usually be less than 500MB.)

 

(Earlier this year, there was a big flap because some manufacturers were accused of shipping drives to reviewers that used MCL technology when the actual shipping drives were using TCL  The issue came to light when users could not duplicate the test results of the reviewers.)

 

You could try swapping which SSD drive you are using to cache these transfers and see if that makes a difference.  (Make sure you move any cached files off that drive to the array first!)

 

I would suggest that you try an experiment.  Copy a block of data to a cached share on Unraid and time the transfer with a stopwatch.  (Ignore the transfer speed reported by the file manager.)  Than copy the same file set back to your PC and time that transfer the same way.  (I actually basically do this as after I make my monthly backups, I copy those backups to a USB3 hard drive that is stored off-site.  My experience is that both times are approximately the same.)  OH , I do do this in the foreground.  I have a feeling that file managers have a much lower priority when they become a background application.

[Gigabyte2]

Thanks for the reply.

In this scenario the cache drive is "Cache_ssd_nvme" that is a Samsung_SSD_970_EVO_Plus_500GB.

I've used this drive as cache for three weeks before that issue comes and the issue still even if I set ssd drive to No in the share's settings (after invoke the mover).

This is the screen of the top during iPhone pictures transfer (hardware is i3-7100 CPU @ 3.90GHz, 16GB RAM and 1gbps LAN)

 

 

[Gigabyte2]

UPDATE:

the issue occurs only if I upload lot of files at the same time (1200 pictures inside a folder), if I upload the folder (and not the files inside it) transfer is at the max speed (6 minutes for 48GB).

If I try to transfer all the pictures in a folder with a thousands more photos the transfer is incredibly slow (8h for 48GB)

 

[Frank1940]

1 hour ago, Gigabyte2 said:

the issue occurs only if I upload lot of files at the same time (1200 pictures inside a folder), if I upload the folder (and not the files inside it) transfer is at the max speed (6 minutes for 48GB).

What exactly are you doing?   By this, I mean

Quote

lot of files at the same time (1200 pictures inside a folder)

How is this being done?  (Normally, when a large group of files are transferred, it is done one file at a time.  If you start two (or more) streams of files transferring simultaneously, things degrade very quickly!!!  Particularity, if you look at what is happening to only one stream.)

 

 

Quote

if I upload the folder (and not the files inside it) transfer is at the max speed (6 minutes for 48GB).

How is this different from what you did in the previous quote?  I would assume that uploading a folder would all of the contents of that folder which would include files and possibly even other folders with their contents.  (However, copying a folder and its contents assures that only one file is being moved at a time!)

 

It would be beneficial to know the OS of the other computer involved in this transfer and the name of the file manager . 

 

 

Edited November 17, 2021 by Frank1940

[Gigabyte2]

Hi, when I said folder it means that I copy a single folder (with a thousand of files inside it), when I said "lot of files at the same time" it means that I select all files inside the folder and I copy them and not the parent folder.

Every operation is made from an iMac with MacOS 11.6.1.

[Frank1940]

At this point, I think you know what will work well and what does NOT work very well.  I don't use any Apple products here so I can't test this scenario.  I don't even want to think as to how I would get a folder with a thousand plus SMALL files in it to see if the same problems exist in a Windows situation.  (Furthermore, I can't imagine even wanting such an monstrosity.  I have had problems locating the file I want in a folder of less than a hundred individual files...) 

 

In the back of my mind is the thought that the algorithm that Apple uses to copy individual files might not scale well to handle thousands of files.  But then maybe the algorithm that Microsoft uses does not either...