eMMC vs SD (N2)

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powerful owl
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eMMC vs SD (N2)

Unread post by powerful owl » Wed Apr 17, 2019 2:44 pm

My results from a fresh Ubuntu Mate installation on a 2GB N2.

8 GB eMMC

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odroid@odroid:~$ dd if=/dev/zero of=test.tmp oflag=direct bs=8M count=64
536870912 bytes (537 MB, 512 MiB) copied, 23.1191 s, 23.2 MB/s
odroid@odroid:~$ dd if=test.tmp of=/dev/null iflag=direct bs=8M count=64
536870912 bytes (537 MB, 512 MiB) copied, 3.54374 s, 151 MB/s
odroid@odroid:~$ iozone -e -I -a -s 100M -r 4k -r 16384k -i 0 -i 1 -i 2
                                                              random    random                                    
              kB  reclen    write  rewrite    read    reread    read     write
          102400       4    15711    12517    24232    24020    24234    13621                                                          
          102400   16384    13108    24609   137442   140731   145389    16282              
          
32GB Toshiba Exceria Pro SD card

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odroid@odroid:~$ dd if=/dev/zero of=test.tmp oflag=direct bs=8M count=64
536870912 bytes (537 MB, 512 MiB) copied, 12.2923 s, 43.7 MB/s
odroid@odroid:~$ dd if=test.tmp of=/dev/null iflag=direct bs=8M count=64
536870912 bytes (537 MB, 512 MiB) copied, 8.04086 s, 66.8 MB/s
odroid@odroid:~$ iozone -e -I -a -s 100M -r 4k -r 16384k -i 0 -i 1 -i 2
                                                              random    random                                    
              kB  reclen    write  rewrite    read    reread    read     write
          102400       4     2061     2039     9912     8611     7454     1536                                                          
          102400   16384    43798    43381    74124    63311    63241    43451                                                          
I was expecting faster peak write speed on the eMMC but I guess the important thing is that it maintains its speed well for small block sizes. I have a 32GB eMMC I will try later.

[Update] 32GB eMMC

Code: Select all

odroid@odroid:~$ dd if=/dev/zero of=test.tmp oflag=direct bs=8M count=64
536870912 bytes (537 MB, 512 MiB) copied, 4.92508 s, 109 MB/s
odroid@odroid:~$ dd if=test.tmp of=/dev/null iflag=direct bs=8M count=64
536870912 bytes (537 MB, 512 MiB) copied, 3.35248 s, 160 MB/s
odroid@odroid:~$ iozone -e -I -a -s 100M -r 4k -r 16384k -i 0 -i 1 -i 2
                                                              random    random                                         
              kB  reclen    write  rewrite    read    reread    read     write
          102400       4    32953    35758    28196    28639    27272    34383                                                          
          102400   16384   108110   108249   158120   159197   158810   108703                                                          
Last edited by powerful owl on Wed Apr 17, 2019 4:55 pm, edited 2 times in total.

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mad_ady
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Re: eMMCS vs SD (N2)

Unread post by mad_ady » Wed Apr 17, 2019 2:53 pm

Bigger emmcs have faster write speeds in general because they can parallelize writes to more chips internally

powerful owl
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Re: eMMCS vs SD (N2)

Unread post by powerful owl » Wed Apr 17, 2019 5:01 pm

mad_ady wrote:
Wed Apr 17, 2019 2:53 pm
Bigger emmcs have faster write speeds in general because they can parallelize writes to more chips internally
I added the 32 GB eMMC above, indeed it is much faster for writes. So you do get more than just storage for the extra $...!

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