[Gluster-devel] [POC] disaster recovery: reconstruct all shards

[Gandalf Corvotempesta]

That's why I'm asking for a native tool from gluster

Il 1 mar 2017 2:46 PM, "Krutika Dhananjay" <kdhananj at redhat.com> ha scritto:

> The caveats are:
>
> 1. A non-existent/missing shard anywhere between offset $SHARD_BLOCK_SIZE
> through ceiling ($FILE_SIZE/$SHARD_BLOCK_SIZE)
> indicates a hole. When you reconstruct data from a sharded file of this
> nature, you need to take care to retain this property.
>
> 2. The above is also true for partially filled shards between offset
> $SHARD_BLOCK_SIZE through ceiling ($FILE_SIZE/$SHARD_BLOCK_SIZE).
> What do I mean by partially filled shards? Shards whose sizes are not
> equal to $SHARD_BLOCK_SIZE.
>
> In the above, $FILE_SIZE can be gotten from the
> 'trusted.glusterfs.shard.file-size' extended attribute on the base file
> (the 0th block).
>
> -Krutika
>
> On Mon, Feb 27, 2017 at 1:45 PM, Gandalf Corvotempesta <
> gandalf.corvotempesta at gmail.com> wrote:
>
>> Which caveats?
>> Anyway, having this recovery tool integrated in gluster could be an
>> appreciable plus to guarantee data recovery natively
>>
>> Il 27 feb 2017 6:02 AM, "Krutika Dhananjay" <kdhananj at redhat.com> ha
>> scritto:
>>
>>> It should be possible to write a script that stitches the different
>>> pieces of a single file together
>>> (although with a few caveats).
>>>
>>> -Krutika
>>>
>>> On Sun, Feb 26, 2017 at 8:52 PM, Gandalf Corvotempesta <
>>> gandalf.corvotempesta at gmail.com> wrote:
>>>
>>>> Would be possible to add a command to use in case of disaster recovery
>>>> (where everything is broken) to recreate files from sharding ?
>>>>
>>>> In example, let's assume a totally down cluster. no trusted pools and
>>>> so on but sysadmin knows which hdd is part of any distributed replica:
>>>>
>>>> hdd1 + hdd2 + hdd3 are distributed and replicated to hdd4 + hdd5 + hdd6
>>>>
>>>> a CLI could traverse hdd1,hdd2,hdd3 and reconstruct all shards
>>>> creating the original, unsharded file.
>>>> _______________________________________________
>>>> Gluster-devel mailing list
>>>> Gluster-devel at gluster.org
>>>> http://lists.gluster.org/mailman/listinfo/gluster-devel
>>>>
>>>
>>>
>
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