On 26-May-09, at 10:21 AM, Frank Middleton wrote:
On 05/26/09 03:23, casper....@sun.com wrote:
And where exactly do you get the second good copy of the data?
From the first. And if it is already bad, as noted previously, this
is no worse than the UFS/ext3 case. If you want total freedom from
this class of errors, use ECC.
If you copy the code you've just doubled your chance of using bad
memory.
The original copy can be good or bad; the second copy cannot be
better
than the first copy.
The whole point is that the memory isn't bad. About once a month, 4GB
of memory of any quality can experience 1 bit being flipped, perhaps
more or less often.
What you are proposing does practically nothing to mitigate "random
bit flips". Think about the probabilities involved. You're testing
one tiny buffer, very occasionally, for an extremely improbable
event. It is also nothing to do with ZFS, and leaves every other byte
of your RAM untested. See the reasoning?
--Toby
...
Cheers -- Frank
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