recommended micro sd card ?

[xalius]

Just tested my USB Stick again, it's a 64GB Sony USB3.0 (dont know the exact model, PID is 0x054c, VID is 0x05b8) here are the results...

Code:

ubuntu@pine64:/mnt$ sudo  iozone -e -I -a -s 100M -r 4k -r 16k -r 512k -r 1024k -r 16384k -i 0 -i 1 -i 2
       Iozone: Performance Test of File I/O
               Version $Revision: 3.429 $
               Compiled for 64 bit mode.
               Build: linux

       Run began: Sun Jun 19 01:08:52 2016

       Include fsync in write timing
       O_DIRECT feature enabled
       Auto Mode
       File size set to 102400 kB
       Record Size 4 kB
       Record Size 16 kB
       Record Size 512 kB
       Record Size 1024 kB
       Record Size 16384 kB
       Command line used: iozone -e -I -a -s 100M -r 4k -r 16k -r 512k -r 1024k -r 16384k -i 0 -i 1 -i 2
       Output is in kBytes/sec
       Time Resolution = 0.000001 seconds.
       Processor cache size set to 1024 kBytes.
       Processor cache line size set to 32 bytes.
       File stride size set to 17 * record size.
                                                             random    random     bkwd    record    stride
             kB  reclen    write  rewrite    read    reread    read     write     read   rewrite      read   fwrite frewrite    fread  freread
         102400       4     6827     5851    10475    10383     5126      196
         102400      16     7675     7773    21236    21252    14183      795
         102400     512    15876    11976    38357    38526    37429     5403
         102400    1024    11973    11278    39063    39085    38639     5687
         102400   16384    13439    10519    41124    41095    41127    12157

iozone test complete.

As you can see, read performance reaches twice the speed of my Samsung card (see above) for large record sizes but the random writes for small block sizes show really bad performance. I wonder if that is due to the ext4 filesystem I put on the stick...