RB751U-2HnD has appeared bad blocks

RouterOS General
1

After the next restart RB751U-2HnD stopped working. Checking has revealed appeared bad blocks.
Only 0.1% but it destroyed the config and broke his restoration with such symptoms:
– run WinBox
– connect to RB by MAC
– go to ‘Files’
– select the stored config
– choose ‘Restore’ and agree with restoration
– RB hasn’t config after reboot :frowning:
Repaired by HW reset to the factory defaults and restore config.

Current state:

       routerboard: yes
             model: 751U-2HnD
     serial-number: 3A6A021A9AAD
  current-firmware: 3.02
  upgrade-firmware: 3.02

                  uptime: 1h45m23s
                  version: 5.23
              free-memory: 17152KiB
             total-memory: 29696KiB
                      cpu: MIPS 24Kc V7.4
                cpu-count: 1
            cpu-frequency: 400MHz
                 cpu-load: 4%
           free-hdd-space: 88932KiB
          total-hdd-space: 126976KiB
  write-sect-since-reboot: 215
         write-sect-total: 92323
               bad-blocks: 0.1%
        architecture-name: mipsbe
               board-name: RB751U-2HnD
                 platform: MikroTik

How it typical for the RB751U-2HnD and how it critical for the further work?

P.S. This is my first experience with RB751U-2HnD and I need only USB port but the seller has no RB750UP available at this time.

2

0.1% is nothing to worry about. 3% or more and you might want a Netinstall, otherwise, still nothing to worry about. There are complex mechanisms to work around “bad blocks” and they can be repaired by reinstalling.

3

Yep, I agree. But when bad blocks spoils the current config it very unpleasantly.

4

It will not spoil config, RouterOS is aware of them, and will not write there

5

Would not write in the future, this is understandable. But how to avoid spoiling the current config by the suddenly appeared bad blocks? I don’t know how MT stores the current config, but it’s worth having in the two copies.

6

everything is stored in RAM, and bad blocks are always monitored before writing to disk. I have not heard about any routers corrupted because of bad blocks

7

everything is stored in RAM

…from NAND and if it’s spoiled by the bad blocks then RB hasn’t the current config after a cold restart.

I have not heard about any routers corrupted because of bad blocks

Me too. I have near a hundred different RB and I confronted with such situation for the first time. Therefore I decided write to a forum.