[Gluster-users] thin arbiter vs standard arbiter

[Ashish Pandey]

I think it should be rephrased a little bit - 

"When one brick is up: Fail FOP with EIO." 
should be 
"When only one brick is up out of 3 bricks: Fail FOP with EIO." 

So we have 2 data bricks and one thin arbiter brick. Out of these 3 bricks if only one brick is UP then we will fail IO. 

--- 
Ashish 


----- Original Message -----

From: "Dmitry Melekhov" <dm at belkam.com> 
To: gluster-users at gluster.org, atumball at redhat.com 
Sent: Thursday, August 2, 2018 4:59:41 PM 
Subject: Re: [Gluster-users] thin arbiter vs standard arbiter 

01.08.2018 22:04, Amar Tumballi пишет: 



This recently added document talks about some of the technicalities of the feature: 

https://docs.gluster.org/en/latest/Administrator%20Guide/Thin-Arbiter-Volumes/ 

Please go through and see if it answers your questions. 

-Amar 



Hello! 

I have question: 

Manual says: 


"When one brick is up: Fail FOP with EIO." 

So, if we have 2 nodes with thin arbiter and only one node is up, i.e. second node is down for some reason, then I/O will be stopped. 
Any reasons to have two nodes then? 

Could you tell me is manual right here or it is misprint? 

Thank you! 



<blockquote>



On Wed, Aug 1, 2018 at 11:09 PM, wkmail < wkmail at bneit.com > wrote: 

<blockquote>
I see mentions of thin arbiter in the 4.x notes and I am intrigued. 

As I understand it, the thin arbiter volume is 

a) receives its data on an async basis (thus it can be on a slower link). Thus gluster isn't waiting around to verify if it actually got the data. 

b) is only consulted in situations where Gluster needs that third vote, otherwise it is not consulted. 

c) Performance should therefore be better because Gluster is only seriously talking to 2 nodes instead of 3 nodes (as in normal arbiter or rep 3) 

Am I correct? 

If so, is thin arbiter ready for production or at least use on non-critical workloads? 

How safe is it for VMs images (and/or VMs with sharding)? 

How much faster is thin arbiter setup over a normal arbiter given that the normal data only really sees the metadata? 

In a degraded situation (i.e. loss of one real node), would having a thin arbiter on a slow link be problematic until everything is healed and returned to normal? 

Sincerely, 

-wk 

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</blockquote>




-- 
Amar Tumballi (amarts) 


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</blockquote>




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