I am waiting for this alternative for btrfs
The company that's been funding bcachefs for the past 6 years has, unfortunately, been hit by a business downturn - they've been affected by the strikes in the media production industry. As such, I'm now having to look for new funding.
Hopefully they find a new company to fund the development of bcachefs. Btrfs has major funding from facebook and others, so hopefully there'll be interest in bcachefs since it has some interesting features over btrfs (namely caching and configurable data placement).
Finally, I've been waiting forever for this. btrfs is a mess and zfs in oracle jail forever. Finally we cna have good COW on linux without stupid hoops.
How is btrfs a mess?
RAID 5/6 is somewhat broken, and some people might consider the lack of built in encryption or support for a cache disk as problems. For some reason it seems popular to blame it for data loss.
That being said, it is my favorite file system and I never had problems with data loss, but I use ECC RAM on my desktop as is strongly recommended if you use btrfs or zfs (another potential downside).
Finally! I hope the encryption will get an audit in the near future. 🙂
I just read through the documentation, and didn't see any mention (in particular, on the mount options page) of wear leveling. btrfs makes an effort to use SSDs well; how does bcachefs fare in this respect?
You're right, there isn't any special effort put towards wear leveling, but the bcache FAQ (NOT bcachefs mind you, but the same should be applicable) mentions this:
#I thought SSDs wore out quickly if you did regular writes to them?
For older SSDs, that was true. Newer SSDs will recognize that a given block is getting heavy writes and will actually swap a heavily written block with a more lightly written block (moving the data transparently and using internal pointers to keep track of the move). This is called "wear leveling" and its use can take a drive whose individual blocks might have tens of thousands of writes before failure and produce an SSD that can support up to millions of writes in a given location by moving data around underneath. Also, keep in mind that unlike (most) standard filesystems that treat SSDs as random access devices that can take any number of writes of any size, bcache understands the write issues in SSDs and tunes its write algorithms to minimize the number of erasures needed. As a side note, what we think of as ''write'' performance problems on SSDs are largely ''erase'' performance problems.
Thank you for finding that!
bcache is inherently designed to be an ssd cache that sits in front of slower bigger disks. Bcachefs is an extension of this into it's own filesystem. iirc the words of the bcache creator were: 'we've implemented 80% of a filesystem here, might as well go the rest of the way'. So how much it thrashes a disk is based on what position you give it in the architecture. The caching ssds are going to be used heavily, taking advantage of their fast random access to manage all random accesses, while sequential operations generally go to the slower disk that's set as the background device. The background disks will tend to be accessed less.
So yeah, it's based on what kind of disk and position in the bcache, and what caching options you enable. If you want to look into it further, bcache is fs agnostic, so if you can find some tests that have been done for bcache enabled for classic linux filesystems, like ext4 and xfs, that include hardware degradation info, you'll probably end up with similar usage and hardware wear with the actual bcachefs.
Does bcachefs prevent bit rot, like zfs and btrfs?
Yeah, although the neat part is that you can configure how much replication it uses on a per-file basis: for example, you can set your personal photos to be replicated three times, but have a tmp directory with no replication at all on the same filesystem.
So like isilon. Nice.
What's the timeline for Grub-2 support for making it a root filesystem?
