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SubjectRe: 2.6.38: XFS/USB/HW issue, or failing USB stick?


On Fri, 18 Mar 2011, Arnd Bergmann wrote:

> On Friday 18 March 2011, Tim Soderstrom wrote:
>
>>>
>>> However, after some amount of time, the errors occur below, is this USB
>>> stick failing? Since it has no SMART, is there any other way to verify
>>> the 'health' of a USB stick?
>>
>> What prompted you to go with XFS over, say, ext2? The journal will generally
>> cause quite a bit more writes onto your USB device. I use ext2 on my CF card
>> in my NAS for that reason (the spinning media is on XFS of course). I know
>> that's not an answer to your problem but thought I would add it as a suggestion :)
>
> Using ext2 on flash media instead of ext3 or other file systems is
> recommended a lot, but the situation is actually much more complex.
> In https://lwn.net/Articles/428584/, I explain how these things work
> under the cover. For a drive that can only have very few erase blocks
> open, using a journaled file system will always mean thrashing, but
> for drives with more open erase blocks, it's probably better to
> use a journal than not.
>
> I still need to do simulations to figure out how this exactly
> ends up on various file systems, and I had not considered XFS
> so far.
Ok, I performed all of the tests and I did not notice any type of failures,
unless I am not interpreting the results correctly..

>
> Getting back to the rogiinal question, I'd recommend testing the
> stick by doing raw accesses instead of a file system. A simple
>
> dd if=/dev/sdX of=/dev/zero iflag=direct bs=4M

root@sysresccd /root % time dd if=/dev/sda of=/dev/zero iflag=direct bs=4M
1960+0 records in
1960+0 records out
8220835840 bytes (8.2 GB) copied, 234.265 s, 35.1 MB/s
dd if=/dev/sda of=/dev/zero iflag=direct bs=4M 0.01s user 1.88s system 0% cpu 3:54.28 total
root@sysresccd /root %

>
> will read the entire stick and report any errors. The corresponding
>
> dd of=/dev/zero of=/dev/sdX oflag=direct bs=4M

.. yes I took a second backup (before wiping) before doing this (below) ..

>
> writes the entire stick. Some media won't report errors on write,
> though, so this might not help you at all.

Ok, here are the results:

root@sysresccd /root % time dd if=/dev/zero of=/dev/sda oflag=direct bs=4M
dd: writing `/dev/sda': No space left on device
1961+0 records in
1960+0 records out
8220835840 bytes (8.2 GB) copied, 283.744 s, 29.0 MB/s
dd if=/dev/zero of=/dev/sda oflag=direct bs=4M 0.01s user 7.14s system 2% cpu 4:43.75 total
root@sysresccd /root %

> I'm also interested in results from flashbench
> (git://git.linaro.org/people/arnd/flashbench.git, e.g. like
> http://lists.linaro.org/pipermail/flashbench-results/2011-March/000039.html)
> That might help explain how the stick failed.

Certainly, testing below, following this:
http://lists.linaro.org/pipermail/flashbench-results/2011-March/000039.html

# ./flashbench --open-au --open-au-nr=1 /dev/sda --blocksize=8192 --erasesize=$[2* 1024 * 1024] --random
2MiB 29.5M/s
1MiB 29.1M/s
512KiB 28.5M/s
256KiB 22.8M/s
128KiB 23.8M/s
64KiB 24.4M/s
32KiB 18.9M/s
16KiB 13.1M/s
8KiB 8.22M/s

# ./flashbench --open-au --open-au-nr=4 /dev/sda --blocksize=8192 --erasesize=$[2* 1024 * 1024] --random
2MiB 25.9M/s
1MiB 21.8M/s
512KiB 15M/s
256KiB 11.9M/s
128KiB 12.1M/s
64KiB 13.6M/s
32KiB 9.81M/s
16KiB 6.41M/s
8KiB 3.88M/s

# ./flashbench --open-au --open-au-nr=5 /dev/sda --blocksize=8192 --erasesize=$[2* 1024 * 1024] --random
2MiB 29.2M/s
1MiB 27.8M/s
512KiB 18.4M/s
256KiB 7.82M/s
128KiB 4.62M/s
64KiB 2.47M/s
32KiB 1.26M/s
16KiB 642K/s
8KiB 327K/s
#

# ./flashbench --open-au --open-au-nr=6 /dev/sda --blocksize=1024 --erasesize=$[2* 1024 * 1024] --random
2MiB 29.2M/s
1MiB 25.6M/s
512KiB 15.2M/s
256KiB 7.8M/s
128KiB 4.73M/s
64KiB 2.53M/s
32KiB 1.3M/s
16KiB 659K/s
8KiB 333K/s
^C
#

(did not run one with 7)

# ./flashbench --findfat --fat-nr=10 /dev/sda --blocksize=1024 --erasesize=$[2* 1024 * 1024] --random
2MiB 22.7M/s 19.1M/s 15.5M/s 13.1M/s 29.5M/s 29.5M/s 29.6M/s 29.6M/s 29.5M/s 29.5M/s
1MiB 20.6M/s 13.3M/s 13.3M/s 20.8M/s 18.1M/s 17.8M/s 18M/s 18.3M/s 18.8M/s 18.6M/s
512KiB 18.4M/s 18.6M/s 18.3M/s 18.1M/s 23.5M/s 23.2M/s 23.5M/s 23.5M/s 23.4M/s 23.4M/s
256KiB 26.9M/s 21.3M/s 21.2M/s 21M/s 21.1M/s 21.2M/s 21.1M/s 21.1M/s 20.6M/s 21M/s
128KiB 22.2M/s 22.3M/s 22.6M/s 21.4M/s 21.5M/s 21.3M/s 21.6M/s 21.3M/s 21.4M/s 21.4M/s
64KiB 23.9M/s 22.6M/s 22.9M/s 23M/s 22.5M/s 22.4M/s 22.4M/s 22.4M/s 22.5M/s 22.4M/s
32KiB 18.2M/s 18.3M/s 18.3M/s 18.3M/s 18.3M/s 18.4M/s 18.3M/s 18.2M/s 18.3M/s 18.3M/s
16KiB 12.9M/s 12.9M/s 13M/s 13M/s 12.9M/s 13M/s 12.9M/s 12.9M/s 12.9M/s 12.9M/s
8KiB 8.14M/s 8.15M/s 8.15M/s 8.15M/s 8.15M/s 8.14M/s 8.14M/s 8.15M/s 8.15M/s 8.06M/s
4KiB 4.07M/s 4.08M/s 4.07M/s 4.06M/s 4.04M/s 4.04M/s 4.04M/s 4.04M/s 4.04M/s 4.04M/s
2KiB 2.02M/s 2.02M/s 2.02M/s 2.02M/s 2.02M/s 2.01M/s 2.01M/s 2.01M/s 2.01M/s 2.02M/s
1KiB 956K/s 954K/s 956K/s 953K/s 947K/s 947K/s 947K/s 950K/s 947K/s 948K/s

Ideas?

Justin.


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