Bad blocks on new routerboard onboard memory

Hardware MikroTik hardware general
1 
                  version: "3.11"
              free-memory: 487192kB
             total-memory: 517236kB
                      cpu: "e500v2"
                cpu-count: 1
            cpu-frequency: 1333MHz
                 cpu-load: 7
           free-hdd-space: 40308kB
          total-hdd-space: 61440kB
  write-sect-since-reboot: 11686
         write-sect-total: 74988
               bad-blocks: 7
        architecture-name: "powerpc"
               board-name: "RB1000"

Just got this board about 7 days ago, should I be seeing bad blocks on the onboard memory already???
I’ve used CF cards in other devices running mikrotik with limited writes (saving graph info every hour) and haven’t had this occur.

2

7 bad blocks isn’t a problem. There could be few bad blocks on boards with the NAND [it could be up to 50 by the standards], RouterOS uses special algorithms to overcome this problem. You have to worry when bad blocks is more than 50 and it’s growing exponentially.

3

… and if it goes over 50, you can fix it with “format NAND” from within the Bootloader setup

4

there are multiple reasons why some block on nand can be marked as bad,

most obvious reason is - block is bad and cannot be written anymore, well that happens very rarely as you need 100K writes to happen on same block and that number is guaranteed, so it can be bigger value.

the other reasons - when writing, there are timeouts (especially on RB500) when routeros wants the answer back from nand, that write happened successfully, if timeout is reached by any reason, routeros marks that block bad.

so, if you see that there are a lot of bad blocks (may happen after several years), and you reinstall routeros and you see that bad blocks are back - only then your nand is bad.

so, no worries if there are some bad blocks

5

Ok, thanks for the explanation.

6

Hi,i don’t want to spam on another thread so i will ask some questions regarding same problem here…
I have 602! bad blocks till now and our router is 3 month old,so what should i do?
It’s rb150 package and 2.9.46 router os
Router is working fine .(nothing abnormal)
Please help and best regards from Kobatz

7

Hi, format NAND in BIOS section, then put RouterOS via Netinstall then upgrade BIOS with /system routerboard upgrade Then check bad blocks again. Use 2.9.51 or higher RouterOS

8

Hi,tnx for a quick answer…
After nand format and upgrade will router preserve all setting’s or i have to enter and configure all everything again?
I’am new to nand formating i searched but couldn’t find much..How do you enter a section for nand formating from winbox and what command do you run?
Thank you in advance

9

First /system backup save name=… in RouterOS . After RouterOS reinstall /system backup load name=…
To enter BIOS use serial nulmodem cable, turn on power then hit any key and you see main BIOS choice.