If you are using distributed-replicate, the max file size is the
capacity available on an individual brick (16gb in this case). if you
use stripe-replicate, it will split the file across all of the bricks. I
believe stripe-replicate is only available in 3.3beta/rc at this time.
Your volume size will always be 64gb, other than if you had 3 nodes fail
at the same time (and you would have data unavailable at that point).
Your total available capacity will be 1/3 the capacity of all your
bricks together due to the replica-3 configuration.
On 4/7/12 9:27 AM, Pascal wrote:
Hello David,
thank you for explaining it.
To sum it up: Your suggestion works like a charm ;)
I still have a follow-up question. I expected the available storage
capacity to be half of the total storage capacity provided by all brick
partitions/volumes.
In my test environment each of the four bricks provides ~16 GB and if
two nodes could fail at the same time, there would just ~32 GB be left.
So I used the df command on a client ...
# df -h /mn/gluster-volume
... and it shows me that ~64 GB are available.
I am not able to store files of a total size of 64 GB on that volume,
isn't it? Can someone explain the result of df to me?
----------
I am not sure, if it is the usual way to write down "solutions" on the
mailing list, but I thing it could be helpful for other people.
node1
- /data
- /exp1
- /exp2
- /exp3
node2
- /data
- /exp1
- /exp2
- /exp3
node3
- /data
- /exp1
- /exp2
- /exp3
node4
- /data
- /exp1
- /exp2
- /exp3
# gluster volume create gluster-volume replica 3 transport tcp \
node1:/data/exp1 node2:/data/exp1 node3:/data/exp1 \
node1:/data/exp2 node2:/data/exp2 node4:/data/exp1 \
node1:/data/exp3 node3:/data/exp2 node4:/data/exp2 \
node2:/data/exp3 node3:/data/exp3 node4:/data/exp3
Am Fri, 06 Apr 2012 21:04:16 -0400
schrieb David Coulson<david@xxxxxxxxxxxxxxxx>:
You need to do 12 bricks across 4 nodes, in 'replica 3' groups. This
would allow you to lose two nodes and still have access to all your
data, as each distributed replica group is across at least 3 of your
4 nodes.
You will need to be deliberate about which 3-way groups end up on
each node so you have appropriate redundancy (e.g. group one does
1,2,3, group two does 1,3,4, three does 2,3,4, four does 1,2,4)
On 4/6/12 8:06 PM, Pascal wrote:
Hello David,
I hope that you will read this, even though your post was written
some days ago.
I was trying to configure your suggestion "with a replica count of
3" and I wasn't able to do it.
My original setup with four nodes: node1, node2, node3, node4.
# gluster volume create gluster-storage replica 2 transport tcp
ip-node1:/data ip-node2:/data ip-node3:/data ip-node4:/data
The result:
Node1 and node2 replicated the files among each other and node3 and
node4 did the same. The replication group of node1 and node2
(group1) distributed the files among the replication group of node3
and node4 (group2).
The problem:
Two hard drives could fail at the same time, but just one hard drive
from each replication group. My aim is to archive something were
any two hard drives could fail.
Trying to setup a replica count of 3 with my four nodes:
# gluster volume create gluster-storage replica 3 transport tcp
ip-node1:/data ip-node2:/data ip-node3:/data ip-node4:/data
number of bricks is not a multiple of replica count
This means to my, that I would need six nodes/bricks and that would
lead me to the same situation as before. Node1, node2 and node3
would build a replication group and node4, node5 and node6 would
build the other replication group and both groups together would
save all the data.
I would still have the problem that two hard drives from one
replication group weren't allowed to fail at the same time.
Did I misunderstood your idea of a "replica count of 3"? Would you
be so kind to explain it to me?
Thanks in advance!
Pascal
Am Thu, 29 Mar 2012 10:47:38 -0400
schrieb David
Coulson<david@xxxxxxxxxxxxxxxx>:
Try doing a distributed-replica with a replica count of 3. Not
really 'RAID-6' comparable, but you can have two nodes fail
without outage.
http://download.gluster.com/pub/gluster/glusterfs/3.2/Documentation/AG/html/sect-Administration_Guide--Setting_Volumes-Distributed_Replicated.html
On 3/29/12 10:39 AM, Pascal wrote:
Hello everyone,
I would like to know if it is possible to setup a GlusterFS
installation which is comparable to a RAID 6? I did some research
in the community and several mailing lists and all I could find
were the similar request from 2009
(http://gluster.org/pipermail/gluster-users/2009-May/002208.html,
http://www.gluster.org/community/documentation/index.ph/Talk:GlusterFS_Roadmap_Suggestions).
I would just like to have a scenario where two GlusterFS
nodes/servers, respectively their hard drives, could fail at the
same time.
Thanks in advance!
Pascal
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