Increasing number of allocated file handles

Ron McKeever rmckeever at earthlink.net
Wed Oct 4 20:13:35 UTC 2006 

ulimit -n 196608 in your bash_profile is larger than your hard limit.

After you changed and increased /proc/sys/fs/file-max as root. There is
still a per user limit of open file descriptors which is set to 1024 by
default.
As that user what does 
ulimit -n show?

Under /etc/security/limits.conf:
oracleas        soft    nofile          4096
oracleas        hard    nofile          131072


The «soft limit» in the first line defines the number of file handles or
open files that the Oracle user will have after login. If the Oracle user
gets error messages about running out of file handles, then the Oracle user
can increase the number of file handles like in this example up to 131072
(«hard limit») by running the following command (as oracle user):
ulimit -n number

I have read that if you set the «hard limit» for nofile for the oracle user
equal to /proc/sys/fs/file-max. This could cause a problem where the user
uses up all the file handles, then the system would run out of file handles.
This could mean that you won't be able to initiate new remote logins any
more since the system won't be able to open any PAM modules which are
required for performing a login.

Now login to the oracle account again since the changes will become
effective for new login sessions only. 
And then re-run your ulimit -n. 


FYI...
# cat /proc/sys/fs/file-nr
39937   19888  131072
|	 |       |
|	 |       |
|      |       maximum open file descriptors
|      total free allocated file descriptors
total allocated file descriptors
(the number of file descriptors allocated since boot)

Ron






-----Original Message-----
From: redhat-sysadmin-list-bounces at redhat.com
[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf Of Dominique
Demore
Sent: Wednesday, October 04, 2006 11:03 AM
To: redhat-sysadmin-list at redhat.com
Subject: Re: Increasing number of allocated file handles

Under /etc/security/limits.conf:
oracleas        soft    nofile          4096
oracleas        hard    nofile          131072
oracleas        soft    nproc           2047
oracleas        hard    nproc           32768


Under the oracleas .bash_profile I have added:
ulimit -n 196608
ulimit -u 16384


What I'm seeing is the number of allocated files (first column under
/proc/sys/fs/file-nr) not changing... Maybe it's
suppose to stay at the same number.
[oracleas at esis oracleas]$ cat /proc/sys/fs/file-nr 
39937   19888   131072
[oracleas at esis oracleas]$ 

redhat-sysadmin-list at redhat.com writes:
>Have you set the limits for the user that’s running your app along with the
>systems?
>
>Ron
>
>-----Original Message-----
>From: redhat-sysadmin-list-bounces at redhat.com
>[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf Of Dominique
>Demore
>Sent: Wednesday, October 04, 2006 10:42 AM
>To: redhat-sysadmin-list at redhat.com
>Subject: Re: Increasing number of allocated file handles
>
>We currently have out license as a processor based. I have placed a call
>with Oracle about this issue.
>
>I had placed all parameters in the sysctl.conf as part of the Oracle
>configuration guide, but it still has not resolved
>it..
>
>Thanks.
>
>-- Dominique
>
>redhat-sysadmin-list at redhat.com writes:
>>Dominique,
>>
>>I'm by far, no Oracle Guru, but I seem to remember there was a static
>>number of handles within Oracle.  And it seems to me that we had to
>>change our licensing.  But that is completely from memory.
>>
>>That was Oracle 9i running on a HP-UX 11 HP 9000 L Class Server
>>
>>Sincerely,
>>Lee Higginbotham
>>Senior IT Technical Analyst
>>100 Bluegrass Commons Blvd., Suite 2200
>>Hendersonville, TN  37075
>>Ph:  615-265-2764
>>Fax:  615-265-2847
>>lee.higginbotham at pic.com
>>-----Original Message-----
>>From: redhat-sysadmin-list-bounces at redhat.com
>>[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf Of Art
>>Wildman
>>Sent: Wednesday, October 04, 2006 1:32 PM
>>To: redhat-sysadmin-list at redhat.com
>>Subject: Re: Increasing number of allocated file handles
>>
>>Dominique Demore wrote:
>>> Hi Everyone,
>>>
>>> On our Oracle Application server, we have noticed that we are running
>>out of file handles. Once the number of used file
>>> handles reaches 0, the application crashes/reset itself.
>>> I have increased the number of file handles from 65536 to 104854, but
>>I am still seeing the problem. Should the number
>>> of allocated file handles be increase also, if so, where is the file
>>to modify it.
>>>
>>> (*note: the second column will hit 0 everyday at ~9:00 when everyone
>>is logging into the system.)
>>> ------
>>> [root at server fs]# cat /proc/sys/fs/file-nr 
>>> 39937   7405    104854
>>> [root at server fs]# 
>>> -------
>>>
>>>
>>> Any thoughts/suggestions,
>>>
>>>   
>>
>>Tuning and Optimizing RHEL for Oracle 9i and 10g Databases (Red Hat 
>>Enterprise Linux, 4, 3, 2.1 - redhat, x86-64)
>>http://www.puschitz.com/TuningLinuxForOracle.shtml#SettingFileHandles
>>...The maximum number of file handles can be changed in the proc file 
>>system without reboot:
>>
>># echo 65536 > /proc/sys/fs/file-max
>>
>>Alternatively, you can use sysctl(8) to change it:
>>
>># sysctl -w fs.file-max=65536
>>
>>To make the change permanent, add or change the following line in the 
>>file /etc/sysctl.conf. This file is used during the boot process.
>>
>># echo "fs.file-max=65536" >> /etc/sysctl.conf
>>
>>-------------------
>>
>>Short Guide to install Oracle 10g on Gentoo Linux (2004.0)
>>http://www.akadia.com/services/ora_linux_install_10g.html
>>
>>...Setting Shell Limits for the Oracle User
>>   Most shells like Bash provide control over various resources like the
>>
>>maximum allowable number of open file descriptors or the maximum number 
>>of processes available to a user.
>>
>>    To see all shell limits, run:
>>
>>    $ ulimit -a
>>
>>Setting Limits for the Maximum Number of Open File Descriptors for the 
>>Oracle User
>>
>>    After you changed and increased /proc/sys/fs/file-max (see: Checking
>>
>>Kernel Parameters), there is still a per user limit of open file 
>>descriptors which is set to 1024 by default:
>>
>>    $ su - oracle
>>    $ ulimit -n
>>    1024
>>
>>    To change this, you have to edit the file /etc/security/limits.conf 
>>as root and make the following changes or add the following lines, 
>>respectively:
>>
>>    # To increase the shell limits for Oracle 10.1.0
>>    oracle soft nproc 2047
>>    oracle hard nproc 16384
>>    oracle soft nofile 1024
>>    oracle hard nofile 65536
>>
>>    The <soft limit> in the first line defines the number of file 
>>handles or open files that the Oracle user will have after login. If the
>>
>>Oracle user gets error messages about running out of file handles, then 
>>the Oracle user can increase the number of file handles like in this 
>>example up to 63536 (<hard limit>) by running the following command:
>>
>>    ulimit -n 63536
>>
>>    Note that we do not recommend to set the <hard limit> for nofile for
>>
>>the oracle user equal to /proc/sys/fs/file-max. If you do that and the 
>>user uses up all the file handles, then the system would run out of file
>>
>>handles. This could mean that you won't be able to initiate new remote 
>>logins any more since the system won't be able to open any PAM modules 
>>which are required for performing a login. That's why we set the hard 
>>limit to 63536 and not to 65536.
>>
>>    You also need to make sure that pam_limits is configured in the file
>>
>>/etc/pam.d/system-auth. This is the PAM module that will read the 
>>/etc/security/limits.conf file. The entry should read like:
>>
>>    session required /lib/security/pam_limits.so
>>    session required /lib/security/pam_unix.so
>>
>>    Now login to the oracle account again since the changes will become 
>>effective for new login sessions only.
>>-------------------
>>
>>File System Primer - Novell CoolSolutionsWiki
>>http://wiki.novell.com/index.php/File_System_Primer
>>
>>
>>EXT3
>>
>>    * Most popular Linux file system, limited scalability in size and
>>      number of files
>>    * Journaled
>>    * POSIX extended access control
>>
>>EXT3 file system is a journaled file system that has the greatest use in
>>
>>Linux today. It is the "Linux" File system. It is quite robust and 
>>quick, although it does not scale well to large volumes nor a great 
>>number of files. Recently a scalability feature was added called htrees,
>>
>>which significantly improved EXT3's scalability. However it is still not
>>
>>as scalable as some of the other file systems listed even with htrees. 
>>It scales similar to NTFS with htrees. Without htrees, EXT3 does not 
>>handle more than about 5,000 files in a directory.
>>
>>-HTH
>>--
>>Art Wildman
>>National Weather Service Office, JAX FL. http://www.srh.noaa.gov/jax
>>"If you choose not to decide, you still have made a choice"
>>-Rush|Freewill
>>
>>--
>>redhat-sysadmin-list mailing list
>>redhat-sysadmin-list at redhat.com
>>https://www.redhat.com/mailman/listinfo/redhat-sysadmin-list
>>
>>--
>>redhat-sysadmin-list mailing list
>>redhat-sysadmin-list at redhat.com
>>https://www.redhat.com/mailman/listinfo/redhat-sysadmin-list
>
>
>
>-----
>Dominique Démoré
>Technical Services Coordinator
>Rainbow District School Board
>69 Young Street
>Sudbury, Ontario
>P3E 3G5
>Tel: (705) 674-3171 x. 258
>Fax: (705) 671-2442
>
>
>--
>redhat-sysadmin-list mailing list
>redhat-sysadmin-list at redhat.com
>https://www.redhat.com/mailman/listinfo/redhat-sysadmin-list
>
>
>--
>redhat-sysadmin-list mailing list
>redhat-sysadmin-list at redhat.com
>https://www.redhat.com/mailman/listinfo/redhat-sysadmin-list



-----
Dominique Démoré
Technical Services Coordinator
Rainbow District School Board
69 Young Street
Sudbury, Ontario
P3E 3G5
Tel: (705) 674-3171 x. 258
Fax: (705) 671-2442


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