Re: [discuss] Cannot receive older ZFS dumps

["Udo Grabowski (IMK)" <udo.grabowski@kit.edu>]

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On 01/08/2024 12:53, Toomas Soome via illumos-discuss wrote:
>
>
>> On 1. Aug 2024, at 13:38, Udo Grabowski (IMK) <udo.grabowski@kit.edu> wrote:
>>
>> Hi,
>>
>> it seems that older zfs images (from zfs send) cannot be imported
>> into recent illumos versions. These are dumps from a "pre-features"
>> zpool. I get
>>
>> ro suntc ~ # cat 32@20100825 | zfs receive -d rpool
>> cannot receive new filesystem stream: invalid backup stream
>
>
> Since we virtually do not develop zfs, it is rather hard to say, but it does sound like bug. However, if you can receive it to pre-feature pool, I would upgrade pre-features pool and then check the send+receive again (from upgraded pool).
>

Did some more testing, could also import it on an 8 years old pool
(illumos-a90d75b) with all the features (known at that time) active or enabled:

   async_destroy
   empty_bpobj
   lz4_compress
   multi_vdev_crash_dump
   spacemap_histogram
   enabled_txg
   hole_birth
   extensible_dataset
   embedded_data
   bookmarks
   filesystem_limits
   large_blocks
   sha512
   skein
   edonr

Unknown at that time were

   large_dnode
   device_removal
   obsolete_counts
   zpool_checkpoint
   spacemap_v2
   allocation_classes
   resilver_defer
   encryption
   bookmark_v2
   userobj_accounting
   project_quota
   log_spacemap

Maybe one of that is to blame for the incompatibility, or it's a completely
different bug. The error appears near the end of the zfs receive.

As I still have the original filesystems, and the old ones are not that large,
I will recreate the dumps.

But in principle, zfs should preserve the ability to import older versions as
much as possible, or at least have some up to date information what versions
are supported for a particular new version. And it should then fail with a
version mismatch (if it is such) as the error message.

By the way, for upgrading older OS versions I tested importing new zfs
dumps into an old zpool (without actually booting into the old OS, but for
booting into the new one and then upgrading the old zpool), but that doesn't
work either (probably expectable), the zfs receive hangs itself into an
uninterruptible state after a while. But I won't complain for that one, for
obvious reasons ...

>> while I can still import those on an older illumos (in oi151.a8).
>>
>> This is what zstreamdump sees:
>>
>> # cat 32@20100825|zstreamdump
>> BEGIN record
>>        hdrtype = 1
>>        features = 0
>>        magic = 2f5bacbac
>>        creation_time = 4c751a60
>>        type = 2
>>        flags = 0x0
>>        toguid = d5549c3062863864
>>        fromguid = 0
>>        toname = Processor/Results/imk/32@20100825
>> END checksum = ac3419bb76a98f7/9a5ac336e407bdf3/c07a3f469bc7e40e/f03a369ef26634ee
>> SUMMARY:
>>        Total DRR_BEGIN records = 1
>>        Total DRR_END records = 1
>>        Total DRR_OBJECT records = 131771
>>        Total DRR_FREEOBJECTS records = 716
>>        Total DRR_WRITE records = 133062
>>        Total DRR_WRITE_BYREF records = 0
>>        Total DRR_WRITE_EMBEDDED records = 0
>>        Total DRR_FREE records = 300918
>>        Total DRR_SPILL records = 0
>>        Total records = 566469
>>        Total write size = 1690867200 (0x64c89600)
>>        Total stream length = 1902392632 (0x71643538)
>>
>> Is this a bug or are "non-feature" dumps in general not importable
>> on "feature"-zpools ?
>> --
>> Dr.Udo Grabowski  Inst.of Meteorology & Climate Research IMK-ASF-SAT
>> https://www.imk-asf.kit.edu/english/sat.php
>> KIT - Karlsruhe Institute of Technology          https://www.kit.edu
>> Postfach 3640,76021 Karlsruhe,Germany T:(+49)721 608-26026 F:-926026
>>
>
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-- 
Dr.Udo Grabowski  Inst.of Meteorology & Climate Research IMK-ASF-SAT
https://www.imk-asf.kit.edu/english/sat.php
KIT - Karlsruhe Institute of Technology          https://www.kit.edu
Postfach 3640,76021 Karlsruhe,Germany T:(+49)721 608-26026 F:-926026


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