Re: [tlug] USB2 external HDD

[Darren Cook <darren@example.com>]

>> I have one of 80GB, connected by USB2 on gentoo, and I didn't do any
>> optimization. "hdparm -t /dev/sda1" gives a buffered disk read of about
>> 25 MB/sec.  I guess that's not really fast (internal disk has 50+
>> MB/sec), but not slow enough that I would notice, since I use it only
>> for backup file transfer between computers.

Thanks for the replies. You are writing more than 1G in a session with
no problems?

I just tried hdparm -t /dev/sda1 on the 2G usb memory stick and get
12MB/sec. But I've never noticed reading is a problem; it is writing
more than 1G that is the problem.

> I tend to find the caching is excessive under 2.6 kernel with USB
> mass-storage devices.

Yes, I've found this too. I wonder if the problems I see could be due to
a buffer filling up, rather than it switching to USB 1? But that doesn't
seem to fit the other evidence (e.g. breaking the copy up into less than
1G portions and doing a umount (i.e. flush) between each is much quicker
overall).

Darren