[Gluster-devel] EHT / DHT
Jan H Holtzhausen
janh at holtztech.info
Tue Nov 25 20:11:19 UTC 2014
STILL doesn’t work … exact same file ends up on 2 different bricks …
I must be missing something.
All I need is for:
/directory1/subdirectory2/foo
And
/directory2/subdirectoryaaa999/foo
To end up on the same brick….
Jan
On 2014/11/25, 8:00 PM, "Jan H Holtzhausen" <janh at holtztech.info> wrote:
>Hmm
>Then something is wrong,
>If I upload 2 identical files, with different paths they only end up on
>the same server 1/4 of the time (I have 4 bricks).
>I’ll test the regex quickly.
>
>BR
>Jan
>
>
>
>
>On 2014/11/25, 7:55 PM, "Shyam" <srangana at redhat.com> wrote:
>
>>On 11/25/2014 02:28 PM, Jan H Holtzhausen wrote:
>>> I think I have it.
>>> Unless I’m totally confused, I can hash ONLY on the filename with:
>>>
>>> glusterfs --volfile-server=a_server --volfile-id=a_volume \
>>> --xlator-option a_volume-dht.extra_hash_regex='.*[/\\\\]' \
>>> /a/mountpoint
>>>
>>> Correct?
>>
>>The hash of a file does not include the full path, it is on the file
>>name _only_. So any regex will not work when the filename remains
>>constant like "myfile".
>>
>>As Jeff explains the option is really to prevent using temporary parts
>>of the name in the hash computation (for rename optimization). In this
>>case, you do not seem to have any tmp parts to the name, like "myfile"
>>and "myfile~" should evaluate to the same hash, so remove all trailing
>>'~' from the name.
>>
>>So I am not sure the above is the option you are looking for.
>>
>>>
>>> Jan
>>>
>>> From: Jan H Holtzhausen <janh at holtztech.info
>>><mailto:janh at holtztech.info>>
>>> Date: Tuesday 25 November 2014 at 9:06 PM
>>> To: <gluster-devel at gluster.org <mailto:gluster-devel at gluster.org>>
>>> Subject: Re: [Gluster-devel] EHT / DHT
>>>
>>>>Are you referring to something else in your request? Meaning, you want
>>>
>>>>/myfile, /dir1/myfile and /dir2/dir3/myfile to fall onto the same
>>>
>>>> bricks/subvolumes and that perchance is what you are looking for?
>>>
>>>
>>> That is EXACTLY whatI am looking for.
>>>
>>> What are my chances?
>>
>>As far as I know not much out of the box. As Jeff explained, the
>>directory distribution/layout considers the GFID of the directory, hence
>>each of the directories in the above example would/could get different
>>ranges.
>>
>>The file on the other hand remains constant "myfile" so its hash value
>>remains the same, but due to the distribution range change as above for
>>the directories, it will land on different bricks and not the same one.
>>
>>Out of curiosity, why is this functionality needed?
>>
>>Shyam
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>
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