I have been wondering the same thing for quite some time after having read this post (which makes a pretty clear case in favour of ECC RAM)...
hxxp://forums.freenas.org/threads/ecc-vs-non-ecc-ram-and-zfs.15449/ ... and the ZFS on Linux FAQ hxxp://zfsonlinux.org/faq.html#DoIHaveToUseECCMemory Moreover, the ZFS community seem to cite this article quite often: hxxp://research.cs.wisc.edu/adsl/Publications/zfs-corruption-fast10.pdf Without having further knowledge on that matter, I tend to believe (but I hope I'm wrong) that BTRFS is as vulnerable as ZFS to memory errors. Since I upgraded recently, it's a bit too late for purchasing ECC-capable infrastructure (change of CPU + motherboard + RAM) so I just chose to ignore this risk by performing a memtest86 right before every scrub (and having my regular backups ready). I've been using ZFS on Linux for almost 5 months (having occasional issues with kernel updates) until last week that I finally switched to BTRFS and I'm happy. As for the reliability of ECC RAM (from what I've read about it) it's just that it corrects single-bit errors and it immediately halts the system when it finds multi-bit errors. On Sat, Jan 18, 2014 at 1:23 AM, Ian Hinder <ian.hin...@aei.mpg.de> wrote: > Hi, > > I have been reading a lot of articles online about the dangers of using ZFS > with non-ECC RAM. Specifically, the fact that when good data is read from > disk and compared with its checksum, a RAM error can cause the read data to > be incorrect, causing a checksum failure, and the bad data might now be > written back to the disk in an attempt to correct it, corrupting it in the > process. This would be exacerbated by a scrub, which could run through all > your data and potentially corrupt it. There is a strong current of opinion > that using ZFS without ECC RAM is "suicide for your data". > > I have been unable to find any discussion of the extent to which this is true > for btrfs. Does btrfs handle checksum errors in the same way as ZFS, or does > it perform additional checks before writing "corrected" data back to disk? > For example, if it detects a checksum error, it could read the data again to > a different memory location to determine if the error existed in the disk > copy or the memory. > > From what I've been reading, it sounds like ZFS should not be used with > non-ECC RAM. This is reasonable, as ZFS' resource requirements mean that you > probably only want to run it on server-grade hardware anyway. But with btrfs > eventually being the default filesystem for Linux, that would mean that all > linux machines, even cheap consumer-grade hardware, would need ECC RAM, or > forego many of the advantages of btrfs. > > What is the situation? > > -- > Ian Hinder > http://numrel.aei.mpg.de/people/hinder > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
