Re: A tiny quesion about the object id

"niejunwei@xxxxxxxxxxx" <niejunwei@xxxxxxxxxxx> · Sun, 4 Oct 2015 22:49:30 +0800

HI, Wheat

Thanks for your reply!

I do not have any special purposes for getting the object id. Each object comprises metadata、data and object id. I think for the "object1", the object id is also same with the metadata, all i want is to get it. By the way, i think the "object1" is just an object name not object id.

If i try to use rbd command instead of rados command to put something in ceph, then we can get object id easily. But why can't we get the meatdata or object id through rados command?

All i want is to study object storage more deeply.

Thanks a million!

Best Wishes

Conan

From: Haomai Wang
Date: 2015-10-04 22:21
To: niejunwei
CC: ceph-users
Subject: Re:  A tiny quesion about the object id
On Sun, Oct 4, 2015 at 6:06 PM, niejunwei <niejunwei@xxxxxxxxxxx> wrote:
> HI, All:
>
> I am new and this is my first time to write an email here, i am very
> appreciate that i can get your help.
>
> I create 3 virtual machines on my personal computer and build a simple test
> ceph storage platform based on these 3 VMs. The host names are ceph-14(the
> leader node)、ceph-15 and ceph-16. Each host with 2 data disks(osds) and each
> data disk with 20 GB. The status of ceph is HEALTH_OK, everything works
> well.
>
> Then i create a test file with name of helloceph, the content is "Hello
> Ceph, You are Awesome like NJW". I put this file in the data pool through
> the command of "rados -p data put object1 helloceph", you can check my steps
> as below:
>
>
> [root@ceph-14 ~]# rados -p data put object1 helloceph
> [root@ceph-14 ~]#
> [root@ceph-14 ~]# rados -p data ls
> object1
> [root@ceph-14 ~]#
> [root@ceph-14 ~]# cd /var/lib/ceph/osd/ceph-1/current/0.3c_head/
> [root@ceph-14 0.3c_head]# ls
> object1__head_BAC5DEBC__0
> [root@ceph-14 0.3c_head]# cat object1__head_BAC5DEBC__0
> Hello Ceph, You are Awesome like NJW
> [root@ceph-14 0.3c_head]#
>
> I am very confused that how can i get the object id of object1 above?
>
> There are 3 parts of an object: metadata、data and object id. I think i can
> get data part of object1 from above outputs, but how can i get object id of
> object1?

What's your purpose of object id. It's just object1 I think. You can
via "rados -h" find the related ops get retrieval data, xattr and
omaps

>
> I searched so much and so long on google, but never get what i want. So i am
> very appreciate that you can give me a guide here!!!
>
>
> Best Wishes
>
> Conan
>
> _______________________________________________
> ceph-users mailing list
> ceph-users@xxxxxxxxxxxxxx
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>

-- 
Best Regards,

Wheat

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