saving "zfs send" to a Windows host

Victor Sudakov vas at
Wed Apr 24 16:39:42 UTC 2019

Nikos Vassiliadis wrote:
> Using ssh as transport is fine. I'd advice against saving zfs streams to
> a non-ZFS filesystem because you will have no way to ensure that your
> stream is OK. A single bit flip will render the stream unusable and you
> will only discover this when you try to receive the stream.

The integrity of the backup cannot be checked with "zfs receive -n",
that is true, but to some extent it can be checked with zstreamdump (or at
least I hope so).

For example, where /var/tmp/bad.zfs is the intentionally corrupt backup:

root at vas:~ # zfs receive -nv d02/kaban < /var/tmp/bad.zfs
would receive full stream of zroot/var/mail at test into d02/kaban at test

root at vas:~ # zfs receive -v d02/kaban < /var/tmp/bad.zfs
receiving full stream of zroot/var/mail at test into d02/kaban at test
cannot receive new filesystem stream: checksum mismatch or incomplete stream

root at vas:~ # zstreamdump < /var/tmp/bad.zfs 
BEGIN record
        hdrtype = 1
        features = 4
        magic = 2f5bacbac
        creation_time = 5cc08e0f
        type = 2
        flags = 0x4
        toguid = 2074530c7350e1e2
        fromguid = 0
        toname = zroot/var/mail at test
invalid checksum
Incorrect checksum in record header.
Expected checksum = 1863eeb012/1c685a9e2c25/16eef022635779/e575d4bbf565c75
        Total DRR_BEGIN records = 1
        Total DRR_END records = 0
        Total DRR_OBJECT records = 3
        Total DRR_FREEOBJECTS records = 1
        Total DRR_WRITE records = 0
        Total DRR_WRITE_BYREF records = 0
        Total DRR_WRITE_EMBEDDED records = 0
        Total DRR_FREE records = 2
        Total DRR_SPILL records = 0
        Total records = 7
        Total write size = 0 (0x0)
        Total stream length = 2496 (0x9c0)
root at vas:~ # 

Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
2:5005/49 at fidonet
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