[CentOS] Quota system over NFS

Dave Ulrick d-ulrick at comcast.net
Thu Oct 11 12:35:15 EDT 2012


I've been trying to implement the quota system for a Linux cluster. I'm 
trying it out on a mini-cluster of 4 CentOS 6.3 VMs. I've named them:

lion-login
lion-sn1
lion-cn01
lion-cn02

All nodes are on the virtual subnet 192.168.56.0/24. lion-sn1 (storage 
node 1) is the NFS server and the other three nodes are the NFS clients. 
/etc/exports on lion-sn1:

/home     192.168.56.0/24(rw)

/etc/fstab on the other nodes:

lion-sn1:/home   /home   nfs defaults,usrquota 0 2

User quotas are enabled on /home. rpc.rquotad is running on all 4 nodes.

I'm having two problems:

1. I've confirmed that /etc/init.d/halt is running 'quotaoff -aug' before 
the file systems are unmounted but the shutdown of lion-sn1 is usually 
delayed for half a minute because a process is supposedly using /home. Any 
suggestions on how I could troubleshoot this?

2. Quotas work fine on lion-sn1 (the NFS server). Here's what happens when 
I copy several large ISOs into a user's home directory:

2. Quotas work fine on lion-sn1 (the NFS server). Here's what happens when
I copy several large ISOs into a user's home directory who's logged onto 
that server:

$ quota
Disk quotas for user ulrick (uid 1000):
      Filesystem  blocks   quota   limit   grace   files   quota   limit 
grace
       /dev/sdc1   68896  921600 1048576            3147       0       0
$ cp -v /mnt/home/images/CentOS-6.* .
`/mnt/home/images/CentOS-6.2-i386-netinstall.iso' -> 
`./CentOS-6.2-i386-netinstall.iso'
`/mnt/home/images/CentOS-6.3-i386-bin-DVD1.iso' -> 
`./CentOS-6.3-i386-bin-DVD1.iso'
sdc1: warning, user block quota exceeded.
sdc1: write failed, user block limit reached.
cp: writing `./CentOS-6.3-i386-bin-DVD1.iso': Disk quota exceeded
`/mnt/home/images/CentOS-6.3-x86_64-bin-DVD1.iso' -> 
`./CentOS-6.3-x86_64-bin-DVD1.iso'
cp: writing `./CentOS-6.3-x86_64-bin-DVD1.iso': Disk quota exceeded
$ quota
Disk quotas for user ulrick (uid 1000):
      Filesystem  blocks   quota   limit   grace   files   quota   limit 
grace
       /dev/sdc1 1048576* 921600 1048576   7days    3150       0       0

On the NFS client nodes, the attempt to use space beyond the hard quota 
limit is prevented but no warning is given for exceeding the soft limit, 
and the message issued for the hard limit excession is 'Input/output 
error' rather than 'Disk quota exceeded'. Note that the 'quota' command 
seems to be working correctly:

$ quota
Disk quotas for user ulrick (uid 1000):
      Filesystem  blocks   quota   limit   grace   files   quota   limit 
grace
lion-sn1:/home/   68896  921600 1048576            3147       0       0
$ cp -v /mnt/home/images/CentOS-6.* .
`/mnt/home/images/CentOS-6.2-i386-netinstall.iso' -> 
`./CentOS-6.2-i386-netinstall.iso'
`/mnt/home/images/CentOS-6.3-i386-bin-DVD1.iso' -> 
`./CentOS-6.3-i386-bin-DVD1.iso'
cp: writing `./CentOS-6.3-i386-bin-DVD1.iso': Input/output error
`/mnt/home/images/CentOS-6.3-x86_64-bin-DVD1.iso' -> 
`./CentOS-6.3-x86_64-bin-DVD1.iso'
cp: writing `./CentOS-6.3-x86_64-bin-DVD1.iso': Input/output error
$ quota
Disk quotas for user ulrick (uid 1000):
      Filesystem  blocks   quota   limit   grace   files   quota   limit 
grace
lion-sn1:/home/ 1048576* 921600 1048576   6days    3150       0       0

Instead of the 'Input/output error', I'd like the user on the NFS client 
systems to see the 'Disk quota exceeded' messages they would get if they 
were logged on to the NFS server. Any suggestions on how I might resolve 
this issue?

Thanks,
Dave
-- 
Dave Ulrick
d-ulrick at comcast.net


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