Re: [gentoo-user] Unable to expand ext4 partition

[Wol <antlists@youngman.org.uk>]

On 05/02/2022 22:16, Julien Roy wrote:
> I didn't - I typically use the Gentoo and Arch wiki when I need 
> information, but will keep that in mind.
> I noticed, on that page, that there's a big bold warning about using 
> post-2019 WD Red drives. Sadly, that's exactly what I am doing, my array 
> is 4xWD60EFAX. I don't know whether that's the cause of the problem. It 
> does say on the wiki that these drives can't be added to existing 
> arrays, so it would make sense. Oh well, lesson learned.

  Ouch. EFAX drives are the new SMR version it seems. You might have 
been lucky, it might have added okay.

The problem with these drives, basically, is you cannot stream data to 
them. They'll accept so much, fill up their CMR buffers, and then stall 
while they do an internal re-organisation. And by the time they start 
responding again, the OS thinks the drive has failed ...

I've just bought a Toshiba N300 8TB for £165 as my backup drive. As far 
as I know that's an okay drive for raid - I haven't heard any bad 
stories about SMR being sneaked in ... I've basically split it in 2, 3TB 
as a spare partition for my raid, and 5TB as backup for my 6TB (3x3) 
raid array.

Look at creating a raid-10 from your WDs, or if you create a new raid-5 
array from scratch using --assume-clean then format it, you're probably 
okay. Replacing SMRs with CMRs will probably work fine so if one of your 
WDs fail, you should be okay replacing it, so long as it's not another 
SMR :-) (If you do a scrub, expects loads of parity errors first time 
:-) but you will probably get away with it if you're careful.

Cheers,
Wol