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from the someday-coming-to-a-phone-near-you? dept.
For those Linux folks out there, imagine merging LVM2, dm-raid, and your file system of choice into an all powerful, enterprise ready, check-summed, redundant, containerized, soft raid, disk pool, ram hungry, demi-god file system. The FreeBSD Handbook is a good start to grep the basic capabilities and function of ZFS[*].
The Ars reports:
A new long-term support (LTS) version of Ubuntu is coming out in April, and Canonical just announced a major addition that will please anyone interested in file storage. Ubuntu 16.04 will include the ZFS filesystem module by default, and the OpenZFS-based implementation will get official support from Canonical.
...
ZFS is used primarily in cases where data integrity is important—it's designed not just to store data but to continually check on that data to make sure it hasn't been corrupted. The oversimplified version is that the filesystem generates a checksum for each block of data. That checksum is then saved in the pointer for that block, and the pointer itself is also checksummed. This process continues all the way up the filesystem tree to the root node, and when any data on the disk is accessed, its checksum is calculated again and compared against the stored checksum to make sure that the data hasn't been corrupted or changed. If you have mirrored storage, the filesystem can seamlessly and invisibly overwrite the corrupted data with correct data.
ZFS was available as a technology preview in Ubuntu 15.10, but the install method was a bit more cumbersome than just apt-get install zfsutils-linux. I for one am excited to see ZFS coming to Linux as it is a phenomenal solution for building NAS devices and for making incremental backups of a file system. Now I just wish Ubuntu would do something about the systemD bug.
[*] According to Wikipedia:
ZFS is a combined file system and logical volume manager designed by Sun Microsystems. The features of ZFS include protection against data corruption, support for high storage capacities, efficient data compression, integration of the concepts of filesystem and volume management, snapshots and copy-on-write clones, continuous integrity checking and automatic repair, RAID-Z and native NFSv4 ACLs.
ZFS was originally implemented as open-source software, licensed under the Common Development and Distribution License (CDDL). The ZFS name is registered as a trademark of Oracle Corporation.
OpenZFS is an umbrella project aimed at bringing together individuals and companies that use the ZFS file system and work on its improvements.
(Score: 2) by ledow on Friday February 19 2016, @11:14AM
A single flipped bit in RAM could hose your EFI and kill your laptop, if recent events are anything to go by.
A single flipped bit in RAM is BAD. As in most likely you'll blue-screen or kernel-panic no matter what the OS or filesystem, and then you're into data loss and corruption that no RAID BBU will save you from.
Though ZFS might be technically worse in that scenario, it's already game-over time for continuing operations, it probably means you're going to lose all service to that PC, have a disk check on next boot at minimum and maybe/maybe not lose the database you were writing to no matter what the filesystem.
Either way, you want to not be relying on that never happening. So ECC RAM or redundant storage and servers at minimum. Once you get there, ECC RAM is bog-standard and a pitiful percentage of the overall cost.
Home PC's? Yeah, maybe that's a problem. But to be honest, you're looking at a "power-user" use case to be using Ubuntu LTS anyway, especially if you're using ZFS, and especially if you're using it on a PC without ECC.
So, really, it's kind of a niche worry.
I speak as someone who had to have a nice guy from IBM/Lenovo visit recently with a very expensive (per GB, was free replacement for me) RAM chip when one of our blades BSOD'd for safety when it detected an ECC error.
Services were affected for about a minute until the replicas took over. We didn't trust the server that were serviced and made it pull back all the replicas from the other machines once it was back up, and checked them. And I'm part of a two-man team in a school, so it's hardly top-end stuff.
A single-bit flip in your RAID card onboard RAM could do untold damage.
A single-bit flip in your RAM isn't that much better.
If it matters to you, only run with ECC and monitoring tools enabled.