Networked File System
If you are doing a NFS Mount and you receive this error
Bad option; for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount. helper programThe Solution is very simple, there is a missing nfs-utils package which you did not install.
dnf install nfs-utilsThis Article is taken from Is NFS session trunking available in RHEL?
Session trunking, whereby one can have multiple TCP connections to the same NFS server with the same IP address is provided by nconnect. This feature is available in RHEL 8
RHSA-2020:4431 for the package(s) kernel-4.18.0-240.el8 or later.
RHBA-2020:4530 for the package(s) nfs-utils-2.3.3-35.el8 libnfsidmap-2.3.3-35.el8 or later.
You can configure on the client side up to 16 connection
[root@nfs-client ~]# mount -t nfs 192.168.0.2:/nfs-share /nfs-share -o nosharecache,nconnect=16You can see by using the command
[root@nfs-client ~]# cat /proc/self/mountstats
......
......
RPC iostats version: 1.1 p/v: 100003/4 (nfs)
xprt: tcp 991 0 2 0 39 13 13 0 13 0 2 0 0
xprt: tcp 798 0 2 0 39 6 6 0 6 0 2 0 0
xprt: tcp 768 0 2 0 39 6 6 0 6 0 2 0 0
xprt: tcp 1013 0 2 0 39 4 4 0 4 0 2 0 0
xprt: tcp 828 0 2 0 39 4 4 0 4 0 2 0 0
xprt: tcp 702 0 2 0 39 2 2 0 2 0 2 0 0
xprt: tcp 783 0 2 0 39 2 2 0 2 0 2 0 0
xprt: tcp 858 0 2 0 39 2 2 0 2 0 2 0 0
.....Someone recorded multiple performance increase when used on Pure Storage acting as a NFS Server. at Use nconnect to effortlessly increase NFS performance
References:
From the NFS Server, do put in the command below. The NFS Server is 192.168.0.1 and the NFS Server port is 2049
# netstat -an | grep 192.168.0.1:2049
tcp 0 0 192.168.0.1:2049 192.168.0.10:965 ESTABLISHED
(192.168.0.10 is the client)
Step 1: Do a Yum Install
# yum install nfs-utils rpcbind
Step 2: Enable the Service at Boot Time
# systemctl enable nfs-server # systemctl enable rpcbind # systemctl enable nfs-lock (it does not need to be enabled since rpc-statd.service is static.) # systemctl enable nfs-idmap (it does not need to be enabled since nfs-idmapd.service is static.)
Step 3: Start the Services
# systemctl start rpcbind # systemctl start nfs-server # systemctl start nfs-lock # systemctl start nfs-idmap
Step 4: Confirm the status of NFS
# systemctl status nfs
Step 5: Create a mount point
# mkdir /shared-data
Step 6: Exports the Share
# vim /etc/exports /shared-data 192.168.0.0/16(rw,no_root_squash)
Step 7: Export the Share
# exportfs -rv
Step 8: Restart the NFS Services
# systemctl restart nfs-server
Step 9: Configure the Firewall
# firewall-cmd --add-service=nfs --zone=internal --permanent # firewall-cmd --add-service=mountd --zone=internal --permanent # firewall-cmd --add-service=rpc-bind --zone=internal --permanent
References:
If you are attempting to unmount a NFS command like
# mount -t nfs -o remount /mnt/nfs # umount /mnt/nfs # umount -f /mnt/nfs # umount -l /mnt/nfs # umount -lf /mnt/nfs
Identify which processes tied to the mount need to be killed by using lsof and fuser:
# lsof | grep /mnt/nfs
lsof command above identifies the PID of the processes associated with the /mnt/nfs share. Kill any processes locking the stale mount.
Try to force umount again after the processes as been killed
# umount -lf
References:
nconnect is included in linux kernel versions >= 5.3. What is nconnect? nconnect enables multiple TCP connections for a single NFS mount. It is easy to implement
At /etc/fstab
mount -t nfs -o rw,nconnect=16 192.168.1.0:/applications /user/localFor more information, do take a look at Session Trunking for NFS available in RHEL-8
References:
Taken from How to increase the number of threads created by the NFS daemon in RHEL 4, 5, 6 and 7?
In case of a NFS server with a high load, it may be advisable to increase the number of the threads created during the nfsd server start up.
Edit the following line in /etc/nfs.conf
% vim /etc/nfs.conf
#[nfsd] # debug=0 threads=64 # host= # port=0 # grace-time=90 # lease-time=90 # udp=y # tcp=y
Testing whether it works….
% cat /proc/net/rpc/nfsd
According to the RH, “The first number is the total number of NFS server threads started. The second number indicates whether at any time all of the threads were running at once. The remaining numbers are a thread count time histogram.”
th 64 0 2.610 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
If you have encountered issues like
mount.nfs: requested NFS version or transport protocol is not supported
OR
mount.nfs4: Protocol not supported
Mount with NFS version 3 (with 4 verbose flags)
% mount -vvvv -t nfs -o vers=3 nfs-server:/share /mnt/nfs
1. Assuming this is your mount command
mount -t nfs -o vers=3 XXX.XXX.XXX.XXX:/myserver/nfs /myclient/nfs
2. And if you are using showmount command from an NFS client and the following are observed
clnt_create: RPC: Program not registered
3. You have to access the NetApp Storage to check the NFS Protocol is enabled. I’m using the Netapp OnCommand System Manager
4. Check that the NFS Client can mount.
showmount --no-headers -e nfs_server / (everyone)
References:
The write-up is taken from RedHat Using nfsstat and nfsiostat to troubleshoot NFS performance issues on Linux
NFS relies on the existing network infrastructure, any glitches on the network may affect the performance of the connection. One of the tools that can be used is nfsstat
% yum install nfs-utils
The nfsstat command displays statistical information about the NFS and Remote Procedure Call (RPC) interfaces to the kernel.
% nfsstat -s
Server rpc stats: calls badcalls badclnt badauth xdrcall 107310012 0 0 0 0
The most important field to check is the badcalls, which represents the total number of calls rejected by the RPC layer. When the badcalls is greater than 0, than the underlying network needs to be checked, as there might be latency.
% nfsstat -c
Client rpc stats: calls retrans authrefrsh 23158 0 23172 Client nfs v3: null getattr setattr lookup access readlink 0 0% 7237 31% 7 0% 1443 6% 7874 34% 11 0% read write create mkdir symlink mknod 578 2% 4548 19% 585 2% 1 0% 0 0% 0 0% remove rmdir rename link readdir readdirplus 0 0% 0 0% 0 0% 0 0% 0 0% 51 0% fsstat fsinfo pathconf commit 25 0% 10 0% 5 0% 781 3%
The client is doing well as it has relatively few retransmission requests. If you are encountering excessive retransmissions, you may want to adjust data transfer buffer sizes, which are specified by the mount command options rsize and size.
Check dropped packet by running the following command on both the server and the client:
% nfsstat -o net Client packet stats: packets udp tcp tcpconn 0 0 0 0
The Linux Cluster 