Thank you Ramon for your answer.
The only thing I can't understand is why to use such a big shard?
The default is 64MB. I thought maybe to decrease it, I wanted to do some
tests on it.
Best regards,
Il giorno ven 6 set 2019 alle ore 23:09 Ramon Selga <ramon.selga at
gmail.com>
ha scritto:
> Hi Cristian,
>
> Both approaches are correct but they have different usable capacity and
> tolerance to node failures.
>
> First one is a full replica 3 meaning you get your total node capacity
> divided by 3, because replica 3, and it tolerates a simultaneous of two
> nodes and very good for split-brain avoidance.
>
> Second one is a replica 2 with arbiter, also very good for split-brain
> avoidance (that's purpose of arbiter bricks). In this case you get your
> total capacity divided by two except a little space going to
> arbiter-bricks, may be less than 1% of normal storage bricks. It tolerates
> one node failure at the same time.
>
> For VM usage remember to enable sharding with a shard size of 256MB at
> least before use volume.
>
> If efficiency between total and usable capacity is a concern for you and
> you think you could tolerate only one node failure at the same time, may I
> suggest you to use a distributed dispersed 3 redundancy 1 volume?. You will
> get your total capacity divided by 3 times 2 (that's 2/3 of total
capacity)
> and this config still tolerates one node failure at the same time.
>
> Hope this helps.
>
> *Ramon Selga*
>
> 934 76 69 10
> 670 25 37 05
>
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>
>
> El 06/09/19 a les 17:11, Cristian Del Carlo ha escrit:
>
> Hi,
>
> I have an environment consisting of 4 nodes ( with large disks).
> I have to create a volume to contain image of virtual machines.
>
> In documentation i read:
>
>
> *Hosting virtual machine images requires the consistency of three-way
> replication, which is provided by three-way replicated volumes, three-way
> distributed replicated volumes, arbitrated replicated volumes, and
> distributed arbitrated replicated volumes. *
>
> So I'm going to confusion to configure this volume.
> I have 4 nodes and I don't want to lose space by dedicating one to the
> function of arbiter.
>
> Would it be reasonable to configure the volume as in these two examples?
>
> # gluster volume create test1 replica 3 \
> server1:/bricks/brick1 server2:/bricks/brick1 server3:/bricks/brick1 \
> server2:/bricks/brick2 server3:/bricks/brick2 server4:/bricks/brick2 \
> server3:/bricks/brick3 server4:/bricks/brick3 server1:/bricks/brick3 \
> server4:/bricks/brick4 server1:/bricks/brick4 server2:/bricks/brick4
>
> # gluster volume create test1 replica 3 arbiter 1 \
> server1:/bricks/brick1 server2:/bricks/brick1
> server3:/bricks/arbiter_brick1 \
> server2:/bricks/brick2 server3:/bricks/brick2
> server4:/bricks/arbiter_brick2 \
> server3:/bricks/brick3 server4:/bricks/brick3
> server1:/bricks/arbiter_brick3 \
> server4:/bricks/brick4 server1:/bricks/brick4
> server2:/bricks/arbiter_brick4
>
> Thanks,
>
> --
>
>
> *Cristian Del Carlo*
>
>
>
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*Target Solutions s.r.l.*
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