Fair enough guys, all good points. I think my major failing was not realising that ZFS will detect a hash mismatch on a READ and then WRITE to fix it (or at least think it's fixed it). Taking that into account I can see how my proposal is flawed.
To be honest the end game with my suggestion was two fold; firstly to get a warning that you need to replace your RAM, and secondly to identify which particular file(s) are broken. I suppose if there was a way to just READ the file from disk without having ZFS do a hash check/fixup, then at least you could actually REALLY compare some hashes without ZFS stomping over the file system. It's also a shame that doing a complete RAM test is such an invasive procedure. If it could be done in userland along side a running NFS then that would be beneficial also.
FYI I'm not bothered about saving cash, I was just thinking about a way to give the thousands of non-ECC users out there an early warning. Personally I will be investing in ECC as soon as I've decided on the motherboard.
To be honest the end game with my suggestion was two fold; firstly to get a warning that you need to replace your RAM, and secondly to identify which particular file(s) are broken. I suppose if there was a way to just READ the file from disk without having ZFS do a hash check/fixup, then at least you could actually REALLY compare some hashes without ZFS stomping over the file system. It's also a shame that doing a complete RAM test is such an invasive procedure. If it could be done in userland along side a running NFS then that would be beneficial also.
FYI I'm not bothered about saving cash, I was just thinking about a way to give the thousands of non-ECC users out there an early warning. Personally I will be investing in ECC as soon as I've decided on the motherboard.