3 ms·
In regards to the second point, this isn't correct for ZFS: "If several files contain the same pieces (blocks) of data or any other pool data occurs more than o
by abrookewood 2y ago
In regards to the second point, this isn't correct for ZFS: "If several files contain the same pieces (blocks) of data or any other pool data occurs more than once in the pool, ZFS stores just one copy of it. Instead of storing many copies of a book it stores one copy and an arbitrary number of pointers to that one copy." [0]. So changing one byte of a large file will not suddenly result in writing the whole file to disk again.
[0] https://www.truenas.com/docs/references/zfsdeduplication/ https://www.truenas.com/docs/references/zfsdeduplication/
- karparov 2y agoNot the whole file but it would duplicate the block. GP didn't claim that the whole file is copied.
- abrookewood 2y agoIt reads like that is what they meant: "modifying one byte of a large file would result in a lot disk activity, as the file system would need to duplicate the file again"
- btilly 2y agoThis applies to modifying a byte. But inserting a byte will change every block from then on, and will force a rewrite. Of course, that is true of most filesystems.
- taneliv 2y agoYeah, I did not write it very clearly. On ZFS, you're right. On a file system that applied deduplication to files and not individual blocks, the file would need to be duplicated again, no matter where and what kind of change was made.