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Reducing Disk IO by Optimizing LVE & CageFS w/ SSD

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  • Reducing Disk IO by Optimizing LVE & CageFS w/ SSD

    Attempting to reduce disk IO generated by CageFS

  • #2
    Hello,

    Im working on a server with the following:

    Code:
    CloudLinux 5.9 (2.6.18-448.3.1.el5.lve0.8.64)
    
    # df -h
    
    Filesystem		Size  Used Avail Use% Mounted on
    
    /dev/sda2		9.9G  2.4G  7.0G  26% /
    
    /dev/sda1		487M   38M  424M   9% /boot
    
    /dev/sda8		864G  741G   80G  91% /home
    
    /dev/sda7		2.0G  154M  1.8G   9% /tmp
    
    /dev/sda6		20G  9.4G  9.4G  51% /usr
    
    /dev/sda5		20G  8.8G   10G  47% /var
    
    /dev/sdb1		1.8T  1.2T  549G  69% /backup
    
    /dev/sdc1		74G  6.2G   64G   9% /var/lib/mysql
    While watching top and iostat, I see extended periods of 100% utilization of /home and /var. These seem to correlate with the following process running and staying near the top of the top output:

    /usr/sbin/cagefsctl --force-update

    /dev/sdc is an SSD drive. Im curious if anyone has any suggestions on reducing the disk IO that the above and the lvestats-server process generate with moving certain files to the SSD as one potential method of accomplishing this goal. Other methods more than welcome.

    I think this may be related: cldetect --cxs-installed
    I couldnt find any documentation on what this does, but I just now ran it, as cxswatch is also running on this server. Does anyone have any info on what this process does and if it can help with disk IO?

    Thanks for any insight!

    Comment


    • #3
      Strange that nobody has answered these questions.
      Could someone shed some light here?

      Thanks!

      Comment


      • #4
        Hi,

        The cagefsctl --force-update process really can cause high disk loads as it check or make filesystem template for all system files (for all what is written in /etc/cagefs/cagefs.mp file), if your ssd has enough capacity and power to handle something more then mysql you can really try to move /usr/share/skeleton and /var/cagefs to it, following documentation could be helpful:



        And, do you have default (unmodified) /etc/cagefs/cagefs.mp ?

        About cldetect --cxs-installed it is for some intrenal use when installing cagefs.

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