Re: RAID on GLUSTER node

Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx> · Wed, 13 Jan 2016 10:05:43 +0530



    +gluster-users

    
    On 01/13/2016 09:44 AM, Pawan Devaiah
      wrote:

    
      We would be looking for redundancy so replicated
        volumes I guess
    
    If replication is going to be there, why additional RAID10? You can
    do just RAID6, it saves on space and replication in glusterfs will
    give redundancy anyways.

    
    Pranith

    
        Thanks,
        Dev
      
      
        On Wed, Jan 13, 2016 at 5:07 PM,
          Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx> wrote:

          
                On 01/13/2016 02:21 AM, Pawan Devaiah wrote:

                
                  Thanks for the response Pranith
                    

                    If we take EC out of the equation and say I go
                      with RAID on the physical disk, do you think
                      GlusterFS is good for the 2 workloads that I
                      mentioned before.
                    

                    Basically it is going to be a NFS storage for
                      VM and data but with different RAIDs, 10 for VM
                      and 6 for data.
                  
                
               What will be the kind of volume you will be using
              with these disks?

                  
                  Pranith
              
                
                      Thanks 
                      Dev
                    
                    
                      On Tue, Jan 12, 2016 at
                        9:46 PM, Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx>
                        wrote:

                        
                              On 01/12/2016 01:26 PM, Pawan Devaiah
                                wrote:

                              
                                Thanks for your response
                                  Pranith and Mathieu,
                                  

                                  Pranith: To answer your question,
                                    I am planning to use this storage
                                    for two main workloads.
                                  

                                  1. As a shared storage for VMs.
                                
                              
                             EC as it is today is not good for
                            this.

                              
                                  2. As a NFS Storage for files.
                                
                              
                             If the above is for storing archive
                            data. EC is nice here.

                                
                                Pranith
                            
                              
                                    We are a online backup company
                                      so we store few hundred Terra
                                      bytes of data.
                                    

                                    Mathieu: I appreciate your
                                      concern, however as a system
                                      admins sometimes we get paranoid
                                      and try to control everything
                                      under the Sun.
                                    I know I can only control what
                                      I can.
                                    

                                    Having said that, No, I have
                                      pair of servers to start with so
                                      at the moment I am just evaluating
                                      and preparing for proof of
                                      concept, after which I am going to
                                      propose to my management, if they
                                      are happy then we will proceed
                                      further.
                                    

                                    Regards,
                                    Dev
                                  
                                  
                                    On Tue, Jan
                                      12, 2016 at 7:30 PM, Mathieu
                                      Chateau <mathieu.chateau@xxxxxxx>
                                      wrote:

                                      
                                        Hello,
                                          

                                          For any system, 36 disks
                                            raise disk failure
                                            probability. Do you plan
                                            GlusterFS with only one
                                            server?
                                          

                                          You should think about
                                            failure at each level and be
                                            prepared for it:
                                          
                                            
                                              Motherboard failure
                                                (full server down)
                                              Disks failure
                                              Network cable failure 

                                              
                                              File system corruption
                                                (time needed for fsck)
                                              File/folder removed by
                                                mistake (backup)
                                            
                                            Using or not raid
                                              depend on your answer on
                                              these questions and
                                              performance needed. 
                                            It also depend how
                                              "good" is raid controller
                                              in your server, like if it
                                              has battery and 1GB of
                                              cache.
                                          
                                          
                                          When many disks are
                                            bought at same time (1
                                            order, serial number close
                                            to each other), they may
                                            fail in near time to each
                                            other (if something bad
                                            happened in manufactory).
                                          I already saw like 3
                                            disks failing in few days.
                                          

                                          just my 2 cents,
                                          

                                            Cordialement,

                                              Mathieu CHATEAU

                                              http://www.lotp.fr
                                          
                                          
                                              2016-01-12
                                                4:36 GMT+01:00 Pranith
                                                Kumar Karampuri <pkarampu@xxxxxxxxxx>:

                                                
                                                      On 01/12/2016
                                                        04:34 AM, Pawan
                                                        Devaiah wrote:

                                                      
                                                        Hi
                                                          All,
                                                          

                                                          We have a
                                                          fairly
                                                          powerful
                                                          server sitting
                                                          at office with
                                                          128 Gig RAM
                                                          and 36 X 4 TB
                                                          drives. I am
                                                          planning to
                                                          utilize this
                                                          server as a
                                                          backend
                                                          storage with
                                                          GlusterFS on
                                                          it.
                                                          I have
                                                          been doing lot
                                                          of reading on
                                                          Glusterfs, but
                                                          I do not see
                                                          any definite
                                                          recommendation
                                                          on having RAID
                                                          on GLUSTER
                                                          nodes.
                                                          Is it
                                                          recommended to
                                                          have RAID on
                                                          GLUSTER nodes
                                                          specially for
                                                          the bricks?
                                                          If Yes,
                                                          is it not
                                                          contrary to
                                                          the latest
                                                          Erasure code
                                                          implemented in
                                                          Gluster or is
                                                          it still not
                                                          ready for
                                                          production
                                                          environment?
                                                          I am
                                                          happy to
                                                          implement RAID
                                                          but my two
                                                          main concern
                                                          are
                                                          1. I want
                                                          to make most
                                                          of the disk
                                                          space
                                                          available.
                                                          2. I am
                                                          also concerned
                                                          about the
                                                          rebuild time
                                                          after disk
                                                          failure on the
                                                          RAID.
                                                        
                                                      
                                                     What is the
                                                    workload you have?

                                                    
                                                    We found in our
                                                    testing that random
                                                    read/write workload
                                                    with Erasure coded
                                                    volumes is not as
                                                    good as we get with
                                                    replication. There
                                                    are enhancements in
                                                    progress at the
                                                    moment to address
                                                    these things which
                                                    we are yet to merge
                                                    and re-test.

                                                    
                                                    Pranith

                                                    
                                                        Thanks
                                                        Dev
                                                        

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