• The Four Hundred
  • Subscribe
  • Media Kit
  • Contributors
  • About Us
  • Contact
Menu
  • The Four Hundred
  • Subscribe
  • Media Kit
  • Contributors
  • About Us
  • Contact
  • Admin Alert: Dealing with i5 Critical Storage Errors,

    April 25, 2007 Joe Hertvik


    Part 1

    Critical storage errors can occur whenever i5 hard drive usage passes 90 percent of available storage space. Above 90 percent, system performance starts to degrade. When storage usage breaches 95 percent, the system can become unstable and turn itself off or spontaneously reboot. While you can’t predict when critical storage errors will occur, there are several things you can do to detect and cleanup storage problems before they crash your system.

    What’s the Disk Facts, Jack?

    This week and next week, I’ll deal with the issues involved in monitoring and correcting critical storage errors or storage overflow conditions. Today, I’ll look at some tricks for monitoring your system for developing storage problems. Next week, I’ll discuss some common reasons why your i5 partition storage may be filling up and show you some simple things that you can do to reduce storage usage.

    The first step in handling unexpected disk usage spikes is to monitor for them. The i5/OS operating system provides the following two monitoring functions to detect hazardous disk overflow situations.

    • Setting a disk drive threshold value that tells the system to start sending error messages when system storage usage exceeds the system’s threshold value. The threshold value can be set inside the System Service Tools menu (SST) or inside the Dedicated Service Tools menu (DST). By default, i5/OS sets this value to 90 percent of disk capability.
    • i5/OS also provides two system values that allow you to designate specific actions which the system will take when the percentage of available hard drive storage falls below a certain level. These system values are the auxiliary storage lower limit value (QSTGLOWLMT) and the auxiliary storage lower limit action (QSTGLOWACN). When available storage falls below the percentage specified in QSTGLOWLMT, the system will trigger the action specified in QSTGLOWACN. By default, the auxiliary storage lower limit is set at 5 percent. The possible actions that you can take after available storage falls below the QSTGLOWMT limit include sending messages, calling a special exit point program for custom processing, ending the system to a restricted state, or powering down the system.

    Besides the information in this article, you can find more information on setting and using these values in a previous article I wrote called Protecting Your System from Critical Storage Errors. Today’s article supplements the info in the previous article and it provides additional information about setting QSTGLOWLMT and QSTGLOWACN. These two storage monitoring settings are effective in helping you identify when problems are starting to occur, but they are more effective when combined with a monitoring and paging program such as Bytware’s Messenger Plus product, which can read system logs and message queues and notify you as a problem is occurring.

    Compensating for the Defaults

    The big problem with IBM’s critical storage notification system is that the i5/OS defaults for these values are set too high to enable administrators to do much more than panic when storage is starting to fill up. So my first line of defense for monitoring disk usage is to set these values to more appropriate levels that will give me more time to react when a problem occurs. In my shops, I usually set the disk drive threshold value to 85 percent and my QSTGLOWLMT limit value (auxiliary storage lower limit) to 15 percent. This provides additional time to analyze and react to storage usage issues before a crisis appears, which creates a more proactive environment for taking care of these issues as they occur.

    However, there is one modification that I need to consider when setting QSTGLOWLMT to a higher value, such as 15 percent available storage. By default, QSTGLOWLMT is set to 5 percent available storage, which tells the system to detect and react to the most critical situation where the system can become unstable and spontaneously crash. When setting your auxiliary storage lower limit value higher than 5 percent, you are changing the rules of the game. Now, you are telling the system to look for possible storage overflow errors as the system approaches critical storage, not when it has already passed the 5 percent available storage rate. Depending on the value that you set QSTGLOWLMT to, your critical storage monitoring can be changed from a reactive situation (looking for storage situations when available storage is less than 5 to 10 percent of all hard drive space) to a proactive situation (where available hard drive space is approaching the critical five-to-ten percent value but has not yet passed that mark yet).

    So if I change my QSTGLOWLMT value to 15 percent from 5 percent, I should also reconsider what action to change my Auxiliary storage lower limit action system value (QSTGLOWACN) to. At this higher value, I should have more available time before I hit the crisis point of 5 percent available storage (95 percent full) and therefore I shouldn’t set QSTGLOWACN to any of its panic-mode values, such as automatically ending the system to a restricted state (*ENDSYS) or immediately powering down the system and restarting it (*PWRDWNSYS). Theoretically, I should have more time to react and correct the problem at 15 percent available storage (85 percent full) than I have at 5 percent availability. At higher values (15 percent and above) QSTGLOWACN should only be set to one of the following milder settings where I can investigate and correct the problem before it gets much worse.

    • *MSG: Which tells the system to send a message to the QSYSOPR message queue
    • *CRITMSG: This tells the system to send a message to the first available user specified in the Critical Messages to user list in my partition’s service attributes. In order for a user to receive a critical message, his user name or user class must be entered in the system service attributes by using the Change Service Attributes command (CHGSRVA). In addition to setting up the Critical Messages user list, you also need to set the Analyze problem automatically service attribute (ANZPRBAUTO) to *YES. ANZPRBAUTO can also be set with the CHGSRVA command.
    • *REGFAC: Submits a job to call any programs that are registered under the auxiliary storage lower limit exit point (QIBM_QWC_QSTGLOWACN). If you set QSTGLOWACN to this option, however, you should make sure that your exit point programs only perform mild functions that don’t have a significant effect on system processing. These programs can be set up to perform standard maintenance for cleaning up system storage or to monitor and email various system personnel as hard drive disk storage is filling up.

    About Our Testing Environment

    All configurations described in this article were tested on an i5 550 box running i5/OS V5R3. Most of the commands used here are also available in earlier versions of the i5/OS and OS/400 operating systems, so the configurations should be usable in prior releases. The QSTGLOWLMT and QSTGLOWACN system values are only available in OS/400 V4R2 and later operating systems, including the newer i5/OS V5Rx systems. However, you may notice minor variations in pre-V5R3 copies of these commands. These differences may be due to incremental command improvements that have occurred from release to release.

    RELATED STORIES

    Protecting Your System from Critical Storage Errors

    The Case of the Mysterious CPI0999 Storage Error



                         Post this story to del.icio.us
                   Post this story to Digg
        Post this story to Slashdot

    Share this:

    • Reddit
    • Facebook
    • LinkedIn
    • Twitter
    • Email

    Tags:

    Sponsored by
    LaserVault

    Integrate Virtual Tape to Automate Your Backups And Strengthen Your Ability To Recover From Cyber Attacks And Disasters

    With most IT departments stretched thin, finding something that can quickly free up IT time is definitely a bonus. That’s why it’s important to stop and take a look at integrating virtual tape into your backup and recovery. Virtual tape is one of those technologies where once you have it, you’ll wonder why you didn’t do it sooner. See a demo and get a $50 gift card.

    But what is it about using virtual tape that makes it so worthwhile? Why is it that so many IBM i shops are already using or considering using virtual tape for all or part of their backup and recovery systems?

    Virtual tape and virtual tape libraries offer a way to both simplify and strengthen backup and recovery operations. By incorporating virtual tape technology, automation of backups becomes possible resulting in hundreds of hours saved annually for IT departments and personnel.

    “We needed to find a replacement that would lower the maintenance cost and reduce complexity of our backup and recovery functions without a major disruption to our operations.” David Fray, Director of Enterprise Systems, ABC Financial

    LaserVault ViTL is a virtual tape and tape library solution developed specifically for use with IBM Power Systems (from AS/400 to iSeries to Power 9s). With ViTL you can:

    • Replace physical tape and tape libraries and eliminate associated delays
    • Automate backup operations, including the ability to purge or archive backups
    • Remotely manage your backups – no need to be onsite with your server
    • Save backups to a dedupe appliance and the cloud
    • Recover your data at lightspeed greatly improving your ability to recover from cyberattacks
    • And so much more

    Sign-up now to see a ViTL online demo and get a $50 Amazon e-gift card when the demo is complete as our way of saying thanks for your time. Plus when you sign-up you’ll receive a free facts comparison sheet on using virtual tape vs tape so you can compare the functionality for yourself.

    Share this:

    • Reddit
    • Facebook
    • LinkedIn
    • Twitter
    • Email

    Sponsored Links

    New Generation Software:  Leading provider of iSeries BI and financial management software
    Vision Solutions:  The first new HA release from the newly merged Vision and iTera companies
    LASERTEC USA:  Fully integrate MICR check printing with your existing application

    IT Jungle Store Top Book Picks

    The System i Pocket RPG & RPG IV Guide: List Price, $69.95
    The iSeries Pocket Database Guide: List Price, $59.00
    The iSeries Pocket Developers' Guide: List Price, $59.00
    The iSeries Pocket SQL Guide: List Price, $59.00
    The iSeries Pocket Query Guide: List Price, $49.00
    The iSeries Pocket WebFacing Primer: List Price, $39.00
    Migrating to WebSphere Express for iSeries: List Price, $49.00
    iSeries Express Web Implementer's Guide: List Price, $59.00
    Getting Started with WebSphere Development Studio for iSeries: List Price, $79.95
    Getting Started With WebSphere Development Studio Client for iSeries: List Price, $89.00
    Getting Started with WebSphere Express for iSeries: List Price, $49.00
    WebFacing Application Design and Development Guide: List Price, $55.00
    Can the AS/400 Survive IBM?: List Price, $49.00
    The All-Everything Machine: List Price, $29.95
    Chip Wars: List Price, $29.95

    Help/Systems Issues Another Update for Robot/SCHEDULE The i5 515 and 525: IBM’s Competitive Analysis

    Leave a Reply Cancel reply

Volume 7, Number 16 -- April 25, 2007
THIS ISSUE SPONSORED BY:

WorksRight Software
Help/Systems
Guild Companies

Table of Contents

  • What Can I Select When I Group?
  • To Shift or Not to Shift: That Is in the Fourth Parameter
  • Admin Alert: Dealing with i5 Critical Storage Errors,
  • The Long and Short of Setting Up Level 40 Security

Content archive

  • The Four Hundred
  • Four Hundred Stuff
  • Four Hundred Guru

Recent Posts

  • IBM Mulls Using DataMigrator as Cloud Warehouse Pipeline
  • PowerTech AV Automatically Detects Ransomware Activity
  • Infor Puts CM3 Project On Hold
  • Four Hundred Monitor, June 29
  • IBM i PTF Guide, Volume 24, Number 26
  • Guild Mortgage Takes The 20-Year Option For Modernization
  • IBM i Licensing, Part 3: Can The Hardware Bundle Be Cheaper Than A Smartphone?
  • Guru: The Finer Points of Exit Points
  • Big Blue Tweaks IBM i Pricing Ahead Of Subscription Model
  • We Still Want IBM i On The Impending Power E1050

Subscribe

To get news from IT Jungle sent to your inbox every week, subscribe to our newsletter.

Pages

  • About Us
  • Contact
  • Contributors
  • Four Hundred Monitor
  • IBM i PTF Guide
  • Media Kit
  • Subscribe

Search

Copyright © 2022 IT Jungle

loading Cancel
Post was not sent - check your email addresses!
Email check failed, please try again
Sorry, your blog cannot share posts by email.