UNIX for Dummies Questions & Answers

Hi,

All the data are kept on Netapp using NFS. some directories are so fast when doing ls but few of them are slow. After doing few times, it becomes fast. Then again after few minutes, it becomes slow again. Can you advise what's going on?
This one directory I am very interested is giving lot of issues. Here is little more about the directory.

Code:

 
/home/portal/htdocs/chip  ( inside this directory has many symbolic links) All of them lives on the Netapp.

Thanks.

When you use NFS to access remote files, it keeps a cache of recently accessed blocks. As time goes by the cache is filled with more recently accessed files. So the first access when the cache is empty is relatively slow and later reads of the same page are relatively fast until those pages have been pushed out of the cache.

The issue you are seeing could also be related to the disk that you are using be setup using "automount" instead of in /etc/fstab.

Take a look at the file "/etc/autofs.conf" (general location to see what is automounted).

Automounted file systems are mapped when accessed and dismounted upon it not being used after a timeout.

Man page for automount:

Code:

 AUTOMOUNT_TIMEOUT
		   The number of seconds after which an automounted file sys-
		   tem will be unmounted if it hasn't been referred to within
		   that period of time.  The default is 10 minutes (600 sec-
		   onds).

Then you do ls in first time, you read directory desctiptor.
If dir contain maaaaaany file (>10k) - this process is not fast.
In next requests ls use cached directory desctiptor and ls work fast