On 14/01/13 15:57, Chris Mason wrote:
On Mon, Jan 14, 2013 at 08:22:36AM -0700, Tomasz Kusmierz wrote:
On 14/01/13 14:59, Chris Mason wrote:
On Mon, Jan 14, 2013 at 04:09:47AM -0700, Tomasz Kusmierz wrote:
Hi,
Since I had some free time over Christmas, I decided to conduct few
tests over btrFS to se how it will cope with "real life storage" for
normal "gray users" and I've found that filesystem will always mess up
your files that are larger than 10GB.
Hi Tom,
I'd like to nail down the test case a little better.
1) Create on one drive, fill with data
2) Add a second drive, convert to raid1
3) find corruptions?
What happens if you start with two drives in raid1? In other words, I'm
trying to see if this is a problem with the conversion code.
-chris
Ok, my description might be a bit enigmatic so to cut long story short
tests are:
1) create a single drive default btrfs volume on single partition ->
fill with test data -> scrub -> admire errors.
2) create a raid1 (-d raid1 -m raid1) volume with two partitions on
separate disk, each same size etc. -> fill with test data -> scrub ->
admire errors.
3) create a raid10 (-d raid10 -m raid1) volume with four partitions on
separate disk, each same size etc. -> fill with test data -> scrub ->
admire errors.
all disks are same age + size + model ... two different batches to avoid
same time failure.
Ok, so we have two possible causes. #1 btrfs is writing garbage to your
disks. #2 something in your kernel is corrupting your data.
Since you're able to see this 100% of the time, lets assume that if #2
were true, we'd be able to trigger it on other filesystems.
So, I've attached an old friend, stress.sh. Use it like this:
stress.sh -n 5 -c <your source directory> -s <your btrfs mount point>
It will run in a loop with 5 parallel processes and make 5 copies of
your data set into the destination. It will run forever until there are
errors. You can use a higher process count (-n) to force more
concurrency and use more ram. It may help to pin down all but 2 or 3 GB
of your memory.
What I'd like you to do is find a data set and command line that make
the script find errors on btrfs. Then, try the same thing on xfs or
ext4 and let it run at least twice as long. Then report back ;)
-chris
Chris,
Will do, just please be remember that 2TB of test data on "customer
grade" sata drives will take a while to test :)
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