How to test SD card on OpenWrt?

Hello there,

I suspect my sdcard isn't going that well, which tools do we have on openwrt to test to see if it's running ok?

does dmesg indicate any errors ?

you could dd the whole card or the partition/FS to /dev/null , see if there are any read errors reported.

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No there are no errors reported but once in a while i notice a weird delay of 10 seconds on requests and that's really weird.

i'm really thinking that the reading is sometimes struggling but i would like to confirm with a command line tool with the openwrt and the pi.

on request for/to what ?

openwrt doesn't really read from the storage during use, pretty much only during boot.

like i said, dd will attempt to read the SD.

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Oh i see so it;s loaded from ram then after boot?

Cool i will try lets see what's wrong.

Fri May  6 11:49:56 2022 kernel: [    1.866050] kmodloader: done loading kernel modules from /etc/modules-boot.d/*
Fri May  6 11:49:56 2022 kernel: [    1.880543] init: - preinit -
Fri May  6 11:49:56 2022 kern.warn kernel: [    1.973595] bcmgenet: Skipping UMAC reset
Fri May  6 11:49:56 2022 kernel: [    1.979003] bcmgenet fd580000.ethernet: configuring instance for external RGMII
Fri May  6 11:49:56 2022 kernel: [    1.986517] bcmgenet fd580000.ethernet eth0: Link is Down
Fri May  6 11:49:56 2022 user.notice kernel: [    6.034010] mount_root: mounting /dev/root
Fri May  6 11:49:56 2022 kern.warn kernel: [    6.038511] EXT4-fs (mmcblk0p2): warning: mounting unchecked fs, running e2fsck is recommended
Fri May  6 11:49:56 2022 kernel: [    6.048274] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
Fri May  6 11:49:56 2022 kern.warn kernel: [    6.072455] FAT-fs (mmcblk0p1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
Fri May  6 11:49:56 2022 user.warn kernel: [    6.083135] urandom-seed: Seeding with /etc/urandom.seed

it's loaded into ram during boot ...

you could try to run the e2fsck, but I'm not sure it'll work if the partition's mounted as rw.

usually indicates a spontaneous reboot. because of cut power, etc.

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That was not the case, it's on so that's why i think it';s weird.

The warning could have been there for a long time, it'd be displayed during every (re)boot until fixed.

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Gotcha, so how do i find what is causing these sudden resolution slowness that happens once in a while?


you haven't told us anything about it, and we're no mind readers :wink:


HAHa Sorry i should have been more specific.

Once in a while i notice that for 10 seconds it's slow to resolve addresses and i'm not sure where this is coming from as i see cpu usage and ram are quite low.

It's maxing 1GB.

which DNSes are used by the clients ?

are you using DoH / DoT ?

which clients experience this, all ? some ?
if some, what OS(es) ?

you should probably create a new thread, containing all that info.


Will do, you are right. Thanks.

Just to make you aware, replacing the SDcard fixed the issue.

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