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History. The ZFS folks, back when, were the only folks making much noise about the association between non-ECC RAM and corrupt data landing on disk. The truth
by __jal 9y ago
History. The ZFS folks, back when, were the only folks making much noise about the association between non-ECC RAM and corrupt data landing on disk.
The truth is, if you care about the notion that your disk should return the same data that software thought it was writing, you should use ECC with any file system. But The ZFS folks made noise about the issue, I think lots of people assumed the reason was that there was something special about ZFS that needed it, and now you have something sort of like an urban legend.
- dom0 9y ago> should return the same data that software thought it was writing Hint: In an OS using a page cache (=every OS) I/O errors are not reliably propagated to applications unless they explicitly sync their dirty pages.
- __jal 9y agoI'm aware of that, but I'm not sure what I'm supposed to take away from it in this context.
- dom0 9y agoThat it's difficult to accurately define "what the application thought it wrote" when considering corruption at various abstraction layers; somewhat similar to calculating checksums over already corrupted data.
- boomboomsubban 9y agoKind of, there are two main things that give ZFS this false reputation. First is an academic paper testing if modern filesystems still needed ECC RAM. They tested ZFS and concluded horrible things could happen to your data without ECC RAM. They found the same about ext2, but that was just a small paragraph people overlooked. So nothing new, but many people are unaware that other FS have the same issue. Second is a moderator on the FreeNAS forums coming up with a scenario where a ZFS scrub would wipe out your data. Developers and other people that have read the code said it couldn't happen as described, but the story was perpetrated on the FreeNAS forums and spread across the net.