101TECH

While working on ny NFS cluster project , I could not mount my nfs exports from clients ( FreBSD & Centos ).

on the FreeBSD client I got these responses :
[udp] server:/data/dir1: Permission denied
on the CentOS client I got these responses:
mount: server:/data/dir1 failed, reason given by server: Permission denied

On the Centos NFS server the logs showed :
mountd[12377]: authenticated mount request from client1:984 for /data/dir1 (/data/dir1)

Turns out there’s a bug in CentOS and modprobe does not mount the nfsd procs , you can fix the issue by adding :

none /proc/fs/nfsd nfsd auto 0 0

to /etc/fstab
or manually ( if you want to make sure that is the issue ) :

/bin/mount -t nfsd nfsd /proc/fs/nfsd

I am working on building a DRBD cluster and as with all cluster tools , you must have a synced time between nodes.

1. install ntp
yum -y install ntp
2. enable ntp on boot
chkconfig ntpd on
3.run a manual time sync before starting the service
ntpdate 0.pool.ntp.org
4. start the service
service ntpd start

trying to umount an nfs or external disk partition and got “partition busy” ?
use fstat -f to find out what the hold up …

-f Restrict examination to files open in the same file systems as
the named file arguments, or to the file system containing the
current directory if there are no additional filename arguments.
For example, to find all files open in the file system where the
directory /usr/src resides, type ``fstat -f /usr/src''.