Date: Wed, 24 Apr 2019 23:39:40 +0700 From: Victor Sudakov <vas@mpeks.tomsk.su> To: freebsd-questions@freebsd.org Subject: Re: saving "zfs send" to a Windows host Message-ID: <20190424163940.GA36280@admin.sibptus.ru> In-Reply-To: <239425b6-a313-3fb8-bc26-321741a4a4d2@gmx.com> References: <20190423054243.GA4659@admin.sibptus.ru> <201904230926.36122.dr.klepp@gmx.at> <239425b6-a313-3fb8-bc26-321741a4a4d2@gmx.com>
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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@vas:~ # zfs receive -nv d02/kaban < /var/tmp/bad.zfs
would receive full stream of zroot/var/mail@test into d02/kaban@test
root@vas:~ # zfs receive -v d02/kaban < /var/tmp/bad.zfs
receiving full stream of zroot/var/mail@test into d02/kaban@test
cannot receive new filesystem stream: checksum mismatch or incomplete stream
root@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@test
invalid checksum
Incorrect checksum in record header.
Expected checksum = 1863eeb012/1c685a9e2c25/16eef022635779/e575d4bbf565c75
SUMMARY:
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@vas:~ #
--
Victor Sudakov, VAS4-RIPE, VAS47-RIPN
2:5005/49@fidonet http://vas.tomsk.ru/
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