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  • Slow SMB performance


    ptr727
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    54 minutes ago, ptr727 said:

    Ok, but why would a SMB option make a difference

    We fixed this other bug first and since SMB is path based, if test program is generating a lot of lookups during write for some reason, could explain it

     

    56 minutes ago, ptr727 said:

    I'll give it a try (case sensitive SMB will break Windows),

    Right, I'd be interested in hearing about a specific case, most things work fine.  However, I realize there could be an app that breaks.  Adding the line to SMB Extras is a quick test/fix, ultimately we'll make a per-share config setting for this.

     

    58 minutes ago, ptr727 said:

    I believe it should be easy to reproduce the results using the tool I've written, so I would suggest you profile the code yourself, rather than wait for my feedback to the experiments.

    Which tool?  Please provide link.  Also debugging these kinds of issues is a 2-way street.  This is not the only issue we have to work on.

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    2 minutes ago, limetech said:

    Which tool?  Please provide link.  Also debugging these kinds of issues is a 2-way street.  This is not the only issue we have to work on.

    I have spent a significant amount of time and effort chasing the SMB performance problem (I immediately noticed the slowdown when I switched from W2K16 to Unraid), so I do think my side of the street has been well worn.

    I referenced the tool I wrote to automate the tests in the last three of my blog posts where I detail my troubleshooting, and every one posted in this thread.

    For completeness, here again: https://github.com/ptr727/DiskSpeedTest

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    5 minutes ago, ptr727 said:

    For completeness, here again

    Thanks for the link.  I don't have any windows code development environment and as soon as I find the half a day to learn this and get it running, I'll take a stab.  In meantime I'll do some testing with linux CIFS and see if I can reproduce similar results.

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    Something else to try:  On Setting/Global Share Settings set Tunable (enable Direct IO) to Yes.

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    I tried with DirectIO yes, and DirectIO yes plus case insensitive yes, no difference (see attached results).

    Given that a disk share over SMB showed good performance, I am sceptical that it is a SMB issue, my money is on a performance problem in the shfs write path.

    DiskSpeedResult_Ubuntu_Cache.xlsx

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    24 minutes ago, ap90033 said:

    So is the issue resolved? 

    No

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    Hi guys, unfortunately I see the same issue with SMB. Here is my results comparing Performance and On Demand CPU profile. Pstates are disabled in config, while running my CPU at max frequency even in idle.


    image.thumb.png.58fdeb338bb5c6be83dbe92533a2065d.png
     

    Here is write speeds once again:
    image.thumb.png.81378591a4babce05b4f6d99e5bb9789.png

     

     

    Currently, this prevents me to switch to unRAID in production. Shouldn't it be the high priority issue? 

     

    My Specs:

    10GbE

    i9-9900

    NVME Cache

    intel_pstate=disable

     

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    On 4/1/2020 at 4:02 PM, rhard said:

    Hi guys, unfortunately I see the same issue with SMB. Here is my results comparing Performance and On Demand CPU profile. Pstates are disabled in config, while running my CPU at max frequency even in idle.

    Which version are you using? I saw a signifcant performance drop starting in 6.8.X, with only partial recovery of performance by modifying Tunable Direct IO and SMB case settings. 6.6.7 at least should be quite a bit faster and doesn't suffer from multistream read/write issues in 6.7.X.

    Edited by golli53
    trimmed quote

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    I just started with unRAID. I am on the latest stable which is 6.8.3. Today I will test SMB on cache disk bypassing unRAID file system. 

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    Here is the results comparing User Share vs DiskShare + Direct IO:
    image.thumb.png.566d5254db5cdacb677ce5509ace106c.png

     

    Write speeds:

    image.thumb.png.f68c338a349a24108474d3bd47a91be4.png

     

    Have no idea what does it mean... 

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  • Status Definitions

     

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