Weird samba performances

    Hello,


    I observe weird samba performances.
    My test are on a single drive (no raid) with J3455 CPU.


    Writing from computer (SSD) to OMV (HDD) : 110MB/s
    Reading the same file from OMV (HDD) to computer (SSD) : 75MB/S


    I know the drive can output at least 100MB/s in R/W on the whole drive space.
    https://www.eteknix.com/toshib…hard-disk-drive-review/5/


    The CPU load is low (35% on one of the 4 cores).


    So ... why is that ?

    Zitat von Koxx

    why is that ?

    Ask your SSD maybe? Most consumer SSD especially with low capacity show a somewhat decent write performance only with small amounts of data. I have 4 120/128 GB SSDs here to play with and while they show sequential write speeds of ~300 MB/s (EVO 840 even exceeding 500 MB/s) this slows down a lot after 1 or a few GB written (my Intel 540 then only writes with 60 MB/s).


    I highly recommend getting 'Helios LanTest' even to test local storage on Windows and compare 'Gigabit Ethernet' and '10 GbE' settings. Since it generates test data from scratch it also allows to test OMV throughput with slow local storage -- see here for details)

    dd test on same drive :


    Code
    root@omv:/storage_main/public# dd if=/dev/zero of=testfile bs=400M count=1 oflag=direct
1+0 records in
1+0 records out
419430400 bytes (419 MB) copied, 3.83105 s, 109 MB/s


root@omv:/storage_main/public# dd if=testfile of=/dev/null
819200+0 records in
819200+0 records out
419430400 bytes (419 MB) copied, 2.86594 s, 146 MB/s

    ok about helio


    Code
    Windows Explorer CopyFile behavior


Starting with Windows 7, customers experience very fast copy speeds to and from the HELIOS PCShare file server. Microsoft internally optimized the CopyFile API which does up to eight asynchronous reads or writes in parallel, each of 32 kByte size. This feature is only available with the CopyFile API or doing asynchronous reads and writes in parallel, e.g. with multiple threads. The new CopyFile is an improvement for SMB servers when clients copy files using the Explorer or the CopyFile API. HELIOS LanTest measures the performance with sequential read/write operations using a specified block size, e.g. 128 kByte using Gigabit Ethernet testing. This reflects much better how applications work because it is very unlikely that applications use multiple asynchronous I/O requests in parallel. Depending on the network, client and server performance in a LanTest measurment of a 1 Gb network may get around 60 MB/sec reading and writing, the Windows Copy file may get around 100 MB due to multiple asynchronous I/Os.

    same bad result from windows/cygwin ...


    clearly the SSD is not the cause


    Code
    { ~ }  » dd if=/cygdrive/z/testfile of=/dev/null
4538049+0 records in
4538048+0 records out
2323480576 bytes (2.3 GB) copied, 34.0116 s, 68.3 MB/s
    Zitat von Koxx

    Writing from computer (SSD) to OMV (HDD) : 110MB/s
    Reading the same file from OMV (HDD) to computer (SSD) : 75MB/S

    That was Windows Explorer performance, by using LanTest you successfully eliminated the SSD as potential bottleneck. With LanTest (not using the more recent 'CopyFile API' but 10 GbE settings using 1MB blocksizes) it looks like this:


    Writing from computer to OMV : 53MB/s
    Reading the same file from OMV to computer : 76MB/S


    Read performance is the same, sequential write performance drops down. In the meantine you tested server storage locally and numbers should allow Windows Explorer <--> Samba sequential performance of ~100 MB/s. So next steps are testing network only (iperf/Jperf) and influence of Samba settings. At least that's the usual procedure when dealing with performance issues.

    not an ethernet board/drivers/bandwith issue:


    my samba config :

    well ...


    I upgraded to kernel 4.11 (I saw some issues with J3455 and kernel 4.9) and rebooted...


    Results :


    OMV -> PC




    PC -> OMV




    I don't know if the reboot or the kernel helped, but the results are perfects.

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