News for hackers. Stuff that matters.

A comment on The State of ZFS on Linux. Parent comment

Re:The State of ZFS on Linux by db48x on Monday September 15, 2014 @07:38PM (#8322219)
It's pretty scary; data on ordinary filesystems just evaporates over time. Undetected bit-flips every few terabytes from the drive itself, flaky cables and controllers, bit flips in your non-ecc ram, ghost writes, misaligned reads, firmware bugs, cheap port multipliers, etc, etc.

I've had a zfs filesystem for a few years now and twice it's detected and corrected an error that would have been silent data corruption in a lesser filesystem.

[ Parent | on HN ]
Re:The State of ZFS on Linux by colin_mccabe on Thursday September 25, 2014 @11:28PM (#8371184)
Serious servers use ECC RAM so bit-flips in memory are not an issue. CRC32 is also pretty robust against single-bit errors. If you think about it, you can't really make any guarantees for non-ECC systems. Flip the wrong bit, and the kernel will delete all your data. There is an if statement somewhere waiting to make this happen, and if the program code can randomly change, eventually it will.

Typical disk corruption patterns are a whole sector of zeroes being read, or reading data that belonged somewhere else. If you want to prove that ZFS's checksum is better, you need to prove that it's better against the patterns of corruption that actually occur.

[ Parent | on HN ]