Home / server / Questions / 545242
In Process
cnst
Asked: 2013-10-11 12:26:18 +0800 CST

zfs on a single device: what happens when a file is corrupted?

  • 772

It is written everywhere that ZFS is helpful even if you only have one physical device, because it will tell you about data corruption due to bit decay and such.

However, can it actually address such corruption?

In other words, are there any notable benefits in running ZFS as a filesystem on a single physical device?

filesystems

3 Answers

  1. If you set the COPIES property for a ZFS filesystem to a value higher than 1, then a file that is corrupt can be repaired because there is at least one more copy available.

    • 5

  2. I guess this depends on how the files gets corrupted...

    Sure, I run ZFS in single device arrangements (atop block devices presented hardware RAID controllers, for instance). I don't know that I'd run with a single physical disk, though.

    As others have mentioned, you can mitigate some of the corruption risk by using the zfs copies= feature. RAID with multiple ZFS-managed devices would still be better. But with ~4 years of ZFS experience, I've never actually encountered corrupted data.

    • 3

  3. Yes, you can have data stored in multiple copies:

    https://blogs.oracle.com/relling/entry/zfs_copies_and_data_protection

    Link from Web Archive project http://web.archive.org/web/20131003025617/https://blogs.oracle.com/relling/entry/zfs_copies_and_data_protection

    So you would vastly reduce available disk space, but potentially be able to recover from a specific area of corruption. (I haven't tried it).

    • 0