Mounting XFS RAID 10 volume over NFS

In certain situations you may want to share a RAID10 volme of NFS as a shared mount point across the instances in the VPC. You can follow the steps below

NFS Server instance:-

1. Install "nfs-utils" package

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$sudo yum install -y nfs-utils
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2. Add the below services at the instance boot up time

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$sudo chkconfig --levels 345 nfs on
$sudo chkconfig --levels 345 nfslock on
$sudo chkconfig --levels 345 rpcbind on
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3. Export the mounted volume to the machines in the VPC cidr block

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$ cat /etc/exports
/mnt/md0    <VPC_CIDR>(rw)
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4. Set the permissions for the mount point and also sub folders if any

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$ ls -l
total 0
drwxrwxrwx 2 root root 69 May 28 06:22 md0
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NOTE - I had give 777 as the permissions for /mnt/md0 folders. Without appropriate permissions, there will be a mount point error. For some reason 766 doesn't work as well.

5. Start the services

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$ sudo service rpcbind start
Starting rpcbind:                                          [  OK  ]
$ sudo service nfs start
Initializing kernel nfsd:                                  [  OK  ]
Starting NFS services:                                     [  OK  ]
Starting NFS mountd:                                       [  OK  ]
Starting NFS daemon:                                       [  OK  ]
Starting RPC idmapd:                                       [  OK  ]
$ sudo service nfslock start
Starting NFS statd:                                        [  OK  ]
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6. Export the mounted RAID volume to all the instances in the VPC

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$ sudo exportfs -av
exporting <VPC_CIDR>:/mnt/md0
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7. Allow ingress rules on nfs server instance's security group for TCP and UDP ports 2049 and 111 for NFS and rpcbind

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$aws ec2 authorize-security-group-ingress --group-id sg-7ad9a61e --protocol tcp --port 2049 --cidr <VPC_CIDR>
$aws ec2 authorize-security-group-ingress --group-id sg-7ad9a61e --protocol udp --port 2049 --cidr <VPC_CIDR>
$aws ec2 authorize-security-group-ingress --group-id sg-7ad9a61e --protocol tcp --port 111 --cidr <VPC_CIDR>
$aws ec2 authorize-security-group-ingress --group-id sg-7ad9a61e --protocol udp --port 111 --cidr <VPC_CIDR>
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NFS client instance:-

1. Install "nfs-utils" package

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$sudo yum install -y nfs-utils
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2. Create a mount point on the instance

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$sudo mkdir /vol
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2. Allow ingress rules for TCP and UDP ports for 2049 and 111 for nfs and rpcbind communication

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$aws ec2 authorize-security-group-ingress --group-id sg-7ad9a61e --protocol tcp --port 2049 --cidr <VPC_CIDR>
$aws ec2 authorize-security-group-ingress --group-id sg-7ad9a61e --protocol udp --port 2049 --cidr <VPC_CIDR>
$aws ec2 authorize-security-group-ingress --group-id sg-7ad9a61e --protocol tcp --port 111 --cidr <VPC_CIDR>
$aws ec2 authorize-security-group-ingress --group-id sg-7ad9a61e --protocol udp --port 111 --cidr <VPC_CIDR>
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3. mount the nfs volume on the nfs client machine

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$sudo mount -t nfs <private ip of nfs server>:/mnt/md0 /vol
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4. Confirm the mounted raid volume shows available disk space

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$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda1            7.8G  1.1G  6.6G  15% /
devtmpfs              490M   56K  490M   1% /dev
tmpfs                 499M     0  499M   0% /dev/shm
<private ip>:/mnt/md0  3.0G   33M  3.0G   2% /vol
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5. Test by writing a file on the mounted nfs volume on the client instance

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$ sudo echo "this is a test" >> /vol/test.txt
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6. Also check the system logs using dmesg

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$ sudo dmesg |tail
[  360.660410] FS-Cache: Loaded
[  360.773794] RPC: Registered named UNIX socket transport module.
[  360.777793] RPC: Registered udp transport module.
[  360.779718] RPC: Registered tcp transport module.
[  360.781867] RPC: Registered tcp NFSv4.1 backchannel transport module.
[  360.845503] FS-Cache: Netfs 'nfs' registered for caching
[  443.240670] Key type dns_resolver registered
[  443.251609] NFS: Registering the id_resolver key type
[  443.253882] Key type id_resolver registered
[  443.255682] Key type id_legacy registered
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