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I learned this the hard way on an old server that did not have ECC. I had a file server happily ticking away using ext4. Converted it to ZFS - and a week late
by wstrange 11y ago
I learned this the hard way on an old server that did not have ECC.
I had a file server happily ticking away using ext4.
Converted it to ZFS - and a week later got file system corruption reported. Ran a very extensive memory test - and sure enough I had bad RAM (but it took 2-3 days for the errors to show up).
In the wild there has to be a ton of corruption that just never gets discovered without end to end checking.
If you have a large jpgs or MKVs - a flipped bit here or there is not going to be apparent.
- ptaipale 11y agoWhy would ZFS be worse than ext4 or anything in this way if you don't have ECC? Genuine question, I don't understand this claim. As far as I can see, ZFS provides protection against some types of failures on disk, which ext4 doesn't. ECC has no impact on that, it protects another dimension.
- FullyFunctional 11y agoOne reason is that you generally perform scrubbing, thus you are potentially rewriting data which would otherwise be at rest. If your memory is bad, this could replace good data with bad. FS that doesn't scrub doesn't have this issue.
- ben0x539 11y agoI read this as they've been having corruption happening all along, but only ZFS detected it?
- wstrange 11y agoYes - exactly. To be clear, ext4 did not cause the corruption - but neither did it detect it or correct it. It happily sent corrupt blocks out to disk. I think this happens a lot more frequently than people realize.