On Mon, 30 Jun 2014 18:21:06 Noah O'Donoghue wrote:
My current setup is a Ubuntu laptop, with 2 external drives.
1X 2TB ext4 for data storage 1X 3TB ext4 for backup (using Crashplan commercial backup software).
My question, is if I change the first drive to btrfs or ZFS, will I gain resiliency from bitrot?
BTRFS in a default configuration will use "dup" for metadata. So a bad metadatablock can be corrected. But a bad data block causes data loss - at least you know you have data loss (as opposed to silent data corruption on older filesystems). ZFS has one more copy of metadata than of data. If you have 1 copy of data (the default) then you have 2 copies of metadata. If you want protection against read errors or data corruption on a dingle disk with ZFS you can use the "copies=" option to use multiple copies. The number of copies of metadata blocks is 1 greater than the number of copies of data. The copies= option can be set on a per "filesystem" (where a ZFS "filesystem" is like a subdirectory on a traditional filesystem) basis.
My understanding is I need 2 drives in at least a RAID 1 to get automatic healing from bitrot,
No, "dup" for BTRFS metadata and "copies=" for data on ZFS give you this on a single disk.
but if I at least use a filesystem with check summing support then I will be able to at least restore my affected files from my Crashplan backups (which are compressed then checksummed and regularly checked for errors automatically) and I won't have the risk of my main drive corrupting my backups, because the read will FAIL if it doesn't pass the checksum.
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