Re: [gentoo-user] Re: problem formatting new 256 GB USB stick

[Michael <confabulate@kintzios.com>]

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On Monday 17 February 2025 23:12:59 Greenwich Mean Time Frank Steinmetzger 
wrote:
> Am Sun, Feb 16, 2025 at 01:41:10PM +0000 schrieb Michael:

> > I just formatted a USB 2.0 8GB stick with mke2fs as a test.  It took 46
> > seconds.  Extrapolating for your 64GB partition it should take ~ 6
> > minutes.  A full 256GB drive would take 24.5 minutes.  I expect a drive
> > enjoying USB 3.0 transfer speeds to take way less than this.
> 
> Your expectations have some vague assumptions:

Yes, I was just trying to point loosely at the order of magnitude as an 
indication of something being faulty in the USB Philip was trying to format.

> - the stick achieves full speed of its USB protocol

I haven't yet found a USB stick which reaches the maximum USB protocol speeds.  
The old USB 2.0 stick I used will not go above 11-12MBps during large writes 
and around twice as fast on sustained reads, well below the advertised USB 2.0 
speed of 60MBps.

> - it keeps that throughput over time

Once buffers are saturated write operations will settle at what the device can 
achieve.  I have observed writes slow down when the empty space left is 
getting low. 

> - the data written grows linearly with the FS size

Usually larger USB drives of the same brand/model tend to have slightly better 
speeds - at least this is what the data sheet for the USB drive Philip bought 
claims.


> USB sticks often have a bad thermal design and throttle down once they get
> hot. And hot they get, especially the high-speed ones.
> 
> If you are curious, use a program like dool or glances to observe the
> device’s actual write throughput during formatting. htop can show this, too,
> but you first need to add a display meter in its config.

I use gkrellms on GUI, and 'watch -d vmstat -d -S M' when on a console, but 
I've also used htop.

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