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Table of Contents

Overview

Some customers may benefit by moving files that NMIS reads/writes to very often to a RAM Disk.  We have seen this improve performance on pollers that have shared storage and 2,000+ nodes provisioned.  The concept is that NMIS will be able to read/write to RAM faster than the shared storage.  Most of the files that NMIS touches very often are found in the nmis8/var directory.

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Warning

This is an advanced configuration technique for large scale deployments with experienced sysadmin.  The benefits for small scale deployments would be negligible.

Procedure

Step #1 - Determine Space Required

There are two questions that quickly come to mind:

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Info

The NMIS Self Test settings may need to be adjusted if the nmis8/var directory is running at a high rate of usage.  Look for the following attributes in nmis8/conf/Config.nmis:

  • 'selftest_min_diskfree_percent' => 10
  • 'selftest_min_diskfree_mb' => 25

 

Step #2 - Create the RAM disk

The RAM disk mount point will need to be created.  In this example we are using /media/ramdisk; be sure to mind the permissions.

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Code Block
[root@TEST]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_nmis64-lv_root
                       16G   11G  4.1G  73% /
tmpfs                 5.9G     0  5.9G   0% /dev/shm
/dev/sda1             477M   75M  377M  17% /boot
/dev/mapper/vg_nmis64_data-lv_data
                      246G   95G  139G  41% /data
/dev/mapper/vg_nmis64-lv_var
                       20G   10G  8.3G  55% /var
tmpfs                1000M   30M  971M   3% /media/ramdisk

Step #3 - Disable NMIS

We need to disable NMIS so that it will not attempt to modify the files as we point nmis8/var to the new RAM disk.  This is easily accomplished by placing a file called 'NMIS_IS_LOCKED' in the nmis8/conf directly as in the following example.

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When none are found continue

Step #4 - Point nmis8/var at the RAM Disk

Since we are planning to put a sym link in /usr/local/nmis8/ for /var pointing at the new RAM disk; verify that in /usr/local/nmis8/conf/Config.nmis nmis8/var points to /usr/local/nmis8/var.  Here's a sample of the directories configuration in that file.

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Code Block
ln -s /media/ramdisk/nmis8/var/ /usr/local/nmis8

Step #5 - Re-enable NMIS

Remove the previously created NMIS lock file.

Code Block
[root@TEST]# rm /usr/local/nmis8/conf/NMIS_IS_LOCKED

Step #6 - Verify

  • move to the /usr/local/nmis8/var directory and execute a 'df -h .' command.  This command should reveal that we are indeed on the ramdisk.

    Code Block
    [root@TEST ~]# cd /usr/local/nmis8/var
    [root@TEST var]# df -h .
    Filesystem      Size  Used Avail Use% Mounted on
    tmpfs          1000M   30M  971M   3% /media/ramdisk
    [root@TEST var]# 
  • Take a look in the /usr/local/nmis8/var directory and confirm that node.json and view.json files have been created. 
  • Verify that the NMIS GUI is functioning normally.
  • Review the nmis8/logs/nmis.log file
  • Check the root user mailbox

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