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Old 11-26-2009, 04:14 AM   #1
jahfarsadiq
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Registered: Jun 2006
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NFS Mount point restrictions - URGENT


Hi All,

I would like to know how many mount points can be configured in NFS clients ?

Are there any restrictions on the number of mount points that can be used in a NFS environment ?

I have been searching for this for quite long but I had no luck.

If anyone knows about, please help me.

Thanks
 
Old 11-26-2009, 04:57 AM   #2
ddaemonunics
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not sure..but on the web they say is 32.
 
Old 11-26-2009, 05:14 AM   #3
ilikejam
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Registered: Aug 2003
Location: Glasgow
Distribution: Fedora / Solaris
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The number of mounts is limited by the number of bits allowed in the minor device number and the number of ports available (for NFS 1,2,3). On Linux <2.6, the minor device numbers were only 8 bits long, so you could have 255 NFS mounts. On 2.6 Linux the minor device numbers are 20 bits long, so in theory you could have 1048575 NFS mounts. You'd run out of network ports first though.

So, for 2.4 and below Linux kernels, it's 255. For 2.6 kernels you're never going to hit the limit unless you're doing something really, really mental.

Dave

P.S. I fail to see what could possibly be URGENT about this.

Last edited by ilikejam; 11-26-2009 at 05:15 AM.
 
Old 11-26-2009, 11:31 PM   #4
jahfarsadiq
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Thanks for the update.

I have a production system where we mount data in /file-share directory. It looks something like this :

xxxxx.xxx.xxxxxxxxxx.net:/vol/xxxxx
2.9T 2.4T 450G 93% /file-share

The system performance was so bad, that we decided to split the mount as below :

xxxxx.xxx.xxxxxxxxxx.net:/vol/xxxxx
2.9T 2.4T 450G 93% /file-share
xxxxx.xxx.xxxxxxxxxx.net:/vol/xxxxx
2.9T 2.4T 450G 93% /file-share-db
xxxxx.xxx.xxxxxxxxxx.net:/vol/xxxxx
2.9T 2.4T 450G 93% /file-share-bdb-share
xxxxx.xxx.xxxxxxxxxx.net:/vol/xxxxx
2.9T 2.4T 450G 93% /file-share-bdb-log

The system performance was going good for a few days and then we again got hit on CPU. So again the mount point /file-share-bdb-share was broken down in to multiple mounts with respect to the project name residing on the mount file-share-bdb-share.

Now the CPU always stands at 110 %

Please advice.
 
Old 11-27-2009, 05:47 AM   #5
ilikejam
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Hi.

I've never seen NFS cause massive CPU usage before. What does 'top' look like?

Dave
 
  


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