Re: Arista filesystem rewinding back 3 years

[William Herrin <bill () herrin us>]

On Tue, Feb 18, 2025 at 12:16 PM Drew Weaver <drew.weaver () thenap com> wrote:
> I found out that this was an issue when I reloaded the switch and the filesystem looks like it rewound itself to 2022 
> in Aboot.

I've seen this before with MicroSD cards in a Raspberry Pi. The card
stops accepting writes but continues to report write success to the
OS. On the Pi, this eventually shows up as seeming filesystem
corruption when blocks are flushed and then reloaded to the disk
cache. Upon reboot, the Pi reverts to the state it was in when the
writes actually stopped happening.

I'm not really sure what the theory behind designing cards this way
is. It does mean that the OS will boot even if the boot process must
write to succeed, but it also means that the OS has no idea that the
flash drive has failed and experiences odd random faults instead.

Regards,
Bill Herrin

-- 
William Herrin
bill () herrin us
https://bill.herrin.us/