Re: [ovirt-users] Hyperconverged Setup and Gluster healing
Hello! On Mon, Apr 24, 2017 at 5:08 PM, FERNANDO FREDIANI < fernando.frediani@upx.com> wrote:
Hi Denis, understood. What if in the case of adding a fourth host to the running cluster, will the copy of data be kept only twice in any of the 4 servers ?
replica volumes can be build only from 2 or 3 bricks. There is no way to make a replica volume from a 4 bricks. But you may combine distributed volumes and replica volumes [1]: gluster volume create test-volume replica 2 transport tcp server1:/b1 server2:/b2 server3:/b3 server4:/b4 test-volume would be like a RAID10 - you will have two replica volumes b1+b2 and b3+b4 combined into a single distributed volume. In that case you will have only two copies of your data. Part of your data will be stored twice on b1 and b2 and another one part will be stored twice at b3 and b4 You will be able to extend that distributed volume by adding new replicas. [1] https://gluster.readthedocs.io/en/latest/Administrator%20Guide/Setting%20Up%...
I personally want three copies of my data, more akin to RAID 6(ish) so in my case replica 3 makes perfect sense. On Mon, Apr 24, 2017 at 11:34 AM, Denis Chaplygin <dchaplyg@redhat.com> wrote:
Hello!
On Mon, Apr 24, 2017 at 5:08 PM, FERNANDO FREDIANI < fernando.frediani@upx.com> wrote:
Hi Denis, understood. What if in the case of adding a fourth host to the running cluster, will the copy of data be kept only twice in any of the 4 servers ?
replica volumes can be build only from 2 or 3 bricks. There is no way to make a replica volume from a 4 bricks.
But you may combine distributed volumes and replica volumes [1]:
gluster volume create test-volume replica 2 transport tcp server1:/b1 server2:/b2 server3:/b3 server4:/b4
test-volume would be like a RAID10 - you will have two replica volumes b1+b2 and b3+b4 combined into a single distributed volume. In that case you will have only two copies of your data. Part of your data will be stored twice on b1 and b2 and another one part will be stored twice at b3 and b4 You will be able to extend that distributed volume by adding new replicas.
[1] https://gluster.readthedocs.io/en/latest/Administrator% 20Guide/Setting%20Up%20Volumes/#creating-distributed-replicated-volumes
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This is a multi-part message in MIME format. --------------DE0189FB210B1FE7509FAA1D Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit RAID 6 doesn't make exactly 3 copies of data. I think storage is too expensive when compared to the total cost of the platform that 3 copies is waste of storage or luxury, given than if you have a permanent failure you still can make a new 2nd copy of the data provided you have storage left for that. On 25/04/2017 10:26, Donny Davis wrote:
I personally want three copies of my data, more akin to RAID 6(ish) so in my case replica 3 makes perfect sense.
On Mon, Apr 24, 2017 at 11:34 AM, Denis Chaplygin <dchaplyg@redhat.com <mailto:dchaplyg@redhat.com>> wrote:
Hello!
On Mon, Apr 24, 2017 at 5:08 PM, FERNANDO FREDIANI <fernando.frediani@upx.com <mailto:fernando.frediani@upx.com>> wrote:
Hi Denis, understood. What if in the case of adding a fourth host to the running cluster, will the copy of data be kept only twice in any of the 4 servers ?
replica volumes can be build only from 2 or 3 bricks. There is no way to make a replica volume from a 4 bricks.
But you may combine distributed volumes and replica volumes [1]:
|gluster volume create test-volume replica 2 transport tcp server1:/b1 server2:/b2 server3:/b3 server4:/b4|
test-volume would be like a RAID10 - you will have two replica volumes b1+b2 and b3+b4 combined into a single distributed volume. In that case you will have only two copies of your data. Part of your data will be stored twice on b1 and b2 and another one part will be stored twice at b3 and b4 You will be able to extend that distributed volume by adding new replicas.
[1] https://gluster.readthedocs.io/en/latest/Administrator%20Guide/Setting%20Up%... <https://gluster.readthedocs.io/en/latest/Administrator%20Guide/Setting%20Up%20Volumes/#creating-distributed-replicated-volumes>
_______________________________________________ Users mailing list Users@ovirt.org <mailto:Users@ovirt.org> http://lists.ovirt.org/mailman/listinfo/users <http://lists.ovirt.org/mailman/listinfo/users>
--------------DE0189FB210B1FE7509FAA1D Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit <html> <head> <meta content="text/html; charset=utf-8" http-equiv="Content-Type"> </head> <body bgcolor="#FFFFFF" text="#000000"> <p>RAID 6 doesn't make exactly 3 copies of data.</p> <p>I think storage is too expensive when compared to the total cost of the platform that 3 copies is waste of storage or luxury, given than if you have a permanent failure you still can make a new 2nd copy of the data provided you have storage left for that.</p> <br> <div class="moz-cite-prefix">On 25/04/2017 10:26, Donny Davis wrote:<br> </div> <blockquote cite="mid:CAMHmko9FfZQErKCyg7crth-ZJode9qWC5DgdjcbM7EirVRUHrA@mail.gmail.com" type="cite"> <div dir="ltr">I personally want three copies of my data, more akin to RAID 6(ish) so in my case replica 3 makes perfect sense. </div> <div class="gmail_extra"><br> <div class="gmail_quote">On Mon, Apr 24, 2017 at 11:34 AM, Denis Chaplygin <span dir="ltr"><<a moz-do-not-send="true" href="mailto:dchaplyg@redhat.com" target="_blank">dchaplyg@redhat.com</a>></span> wrote:<br> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div dir="ltr">Hello!<br> <div class="gmail_extra"><br> <div class="gmail_quote">On Mon, Apr 24, 2017 at 5:08 PM, FERNANDO FREDIANI <span dir="ltr"><<a moz-do-not-send="true" href="mailto:fernando.frediani@upx.com" target="_blank">fernando.frediani@upx.com</a>></span> wrote:<br> <blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex" class="gmail_quote"> <div bgcolor="#FFFFFF"> <p>Hi Denis, understood.<br> What if in the case of adding a fourth host to the running cluster, will the copy of data be kept only twice in any of the 4 servers ?</p> </div> </blockquote> <div><br> </div> <div>replica volumes can be build only from 2 or 3 bricks. There is no way to make a replica volume from a 4 bricks. <br> <br> </div> <div>But you may combine distributed volumes and replica volumes [1]:<br> <br> <pre><code class="m_4650192000417937643gmail-hljs m_4650192000417937643gmail-sql">gluster volume <span class="m_4650192000417937643gmail-hljs-operator"><span class="m_4650192000417937643gmail-hljs-keyword">create</span> test-volume replica <span class="m_4650192000417937643gmail-hljs-number">2</span> transport tcp server1:/b1 server2:/b2 server3:/b3 server4:/b4</span></code></pre> test-volume would be like a RAID10 - you will have two replica volumes b1+b2 and b3+b4 combined into a single distributed volume. In that case you will<br> have only two copies of your data. Part of your data will be stored twice on b1 and b2 and another one part will be stored twice at b3 and b4<br> You will be able to extend that distributed volume by adding new replicas.<br> <br> </div> <div><br> [1] <a moz-do-not-send="true" href="https://gluster.readthedocs.io/en/latest/Administrator%20Guide/Setting%20Up%..." target="_blank">https://gluster.readthedocs.<wbr>io/en/latest/Administrator%<wbr>20Guide/Setting%20Up%<wbr>20Volumes/#creating-<wbr>distributed-replicated-volumes</a><br> </div> </div> </div> </div> <br> ______________________________<wbr>_________________<br> Users mailing list<br> <a moz-do-not-send="true" href="mailto:Users@ovirt.org">Users@ovirt.org</a><br> <a moz-do-not-send="true" href="http://lists.ovirt.org/mailman/listinfo/users" rel="noreferrer" target="_blank">http://lists.ovirt.org/<wbr>mailman/listinfo/users</a><br> <br> </blockquote> </div> <br> </div> </blockquote> <br> </body> </html> --------------DE0189FB210B1FE7509FAA1D--
participants (3)
-
Denis Chaplygin -
Donny Davis -
FERNANDO FREDIANI