gvinum raid5 vs. ZFS raidz

Paul Kraus paul at kraus-haus.org
Tue Aug 26 13:50:41 UTC 2014

On Aug 26, 2014, at 2:41, Scott Bennett <bennett at sdf.org> wrote:

> Paul Kraus <paul at kraus-haus.org> wrote:
>> On Aug 22, 2014, at 5:40, Scott Bennett <bennett at sdf.org> wrote:
>>> What I'm seeing here is ~2 KB of errors out
>>> of ~1.1TB, which is an error rate (in bytes, not bits) of ~1.82e+09, and the
>>> majority of the erroneous bytes I looked at had multibit errors.  I consider
>>> that to be a huge change in the actual device error rates, specs be damned.
>> That seems like a very high error rate. Is the drive reporting those errors or are they getting past the drive?s error correction and showing up as checksum errors in ZFS ? A drive that is throwing that many errors is clearly defective or dying.
>     I'm not using ZFS yet.  Once I get a couple more 2 TB drives, I'll give
> it a shot.
>     The numbers are from running direct comparisons between the source file
> and the copy of it using cmp(1).  In one case, I ran the cmp twice and got
> identical results, which I interpret as an indication that the errors are
> occurring during the writes to the target disk during the copying.

Wow. That implies you are hitting a drive with a very high uncorrectable error rate since the drive did not report any errors and the data is corrupt. I have yet to run into one of those.

Paul Kraus
paul at kraus-haus.org

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