Re: [gentoo-user] Is there a way to misconfigure USB ports in the kernel?

[Michael <confabulate@kintzios.com>]

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On Wednesday, 25 November 2020 17:37:15 GMT Dr Rainer Woitok wrote:
> Greetings,
> 
> since my old  64 GB Verbatim USB sticks  became too small,  I bought two
> new 128 GB  Philips sticks.   Because I need  to read  and write them on
> both, a stand-alone Windows laptop (not connected to the internet) runn-
> ing Windows Vista and Cygwin and my Gentoo laptop, I encrypted them with
> old TrueCrypt  on the Windows box,  using them under Gentoo in TrueCrypt
> compatibility mode.
> 
> This worked  well with the Verbatim  USB sticks  (which probably are USB
> 2.0),  but while reading the new USB 3.0 Philips USB sticks is signific-
> antly faster  than reading the old Verbatim USB sticks,  writing to them
> is slow as hell under Gentoo.   And writing to the Philips USB sticks on
> the old Vista laptop  with USB 2.0 ports  clearly outperforms writing to
> them using the Gentoo laptop's USB 3.0 ports.
> 
> This could be a problem with TrueCrypt/VeraCrypt or with somehow miscon-
> figured USB ports.   To check for the latter  I provide below all kernel
> configuration variables I regard USB related in the hope that some know-
> ledgable people might find a glitch in there:

Check dmesg to see if initialisation of the USB 3.0 drive throws up any 
errors.  Then check 'lsusb -t' to make sure it has been recognised as a USB 
3.0.

If write operations without TrueCrypt/VeraCrypt are equally slow, then 
obviously the problem is not with encryption.

I've read in a number of articles the erase block size on most USB flash 
(NAND) is 128KB, which incurs a lot of operations on a write, when using Linux 
with its 4K size sectors.  Partitioning the USB drive to use 128KB sectors and 
then aligning the fs on it should improve matters.

I found this article which mentions an experiment with ext4 fs.  A more 
effective search should hopefully bring up examples on FAT fs.

HTH.

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