Messages in this thread | | | Date | Mon, 18 Jun 2007 21:37:26 +0400 | From | Vladislav Bolkhovitin <> | Subject | Re: [ANNOUNCE] Btrfs: a copy on write, snapshotting FS |
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Chris Mason wrote: > Hello everyone, > > After the last FS summit, I started working on a new filesystem that > maintains checksums of all file data and metadata. Many thanks to Zach > Brown for his ideas, and to Dave Chinner for his help on > benchmarking analysis. > > The basic list of features looks like this: > > * Extent based file storage (2^64 max file size) > * Space efficient packing of small files > * Space efficient indexed directories > * Dynamic inode allocation > * Writable snapshots > * Subvolumes (separate internal filesystem roots) > - Object level mirroring and striping > * Checksums on data and metadata (multiple algorithms available) > - Strong integration with device mapper for multiple device support > - Online filesystem check > * Very fast offline filesystem check > - Efficient incremental backup and FS mirroring
I would also suggest one more feature: support for block level de-duplication. I mean:
1. Ability for Btrfs to have blocks in several files to point to the same block on disk
2. Support for new syscall or IOCTL to de-duplicate as a single transaction two or more blocks on disk, i.e. link them to one of them and free others
3. De-de-duplicate blocks on disk, i.e. copy them on write
I suppose that de-duplication itself would be done by some user space process that would scan files, determine blocks with the same data and then de-duplicate them by using syscall or IOCTL (2).
That would be very usable feature, which in most cases would allow to shrink occupied disk space on 50-90%.
Vlad - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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