A common task in a sysadmin’s life is to assist to the changes which are affecting the SAN network. At smaller organizations it could be that besides the system administrator role you also need to manage the storage side. So here’s a post which might help you if you need to check the status of [...]
By Viktor Balogh
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Also posted in HP-UX system administration, Monitoring, Servers, Storage
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Tagged active/active, active/passive, EMC PowerPath, FC, fiber, HP Secure Path, hp-ux 11iv3, ioscan, mass storage stack, multipathing, offline, online, path, SAN, SAN path
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If you do performance tuning or troubleshooting with glance probably you have observed the terms logical I/O and physical I/O. This post is to clarify these shortly: Physical I/O: the traffic toward the storage subsystem. Logical I/O: the requests which come from running processes and threads trough system calls. If the requested data is not [...]
By Viktor Balogh
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Also posted in Resource management, System Internals
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Tagged awr, glance, I/O, iostat, logical I/O, performance tuning, physical I/O, sar, statspack, troubleshooting
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The Common Desktop Environment (CDE) has many screensavers for use, you can select which you like the most from the Style Manager Screen menu. There is the screen saver action definition, which describes each screen saver for the desktop environment, it is a metadata which contains the short name of the screensaver and the command [...]
If the system becomes uncontrollable, the last resort is to push the TOC button or run the TC command from the GSP. This will cause the system to generate a crash dump under /var/adm/crash. By analyzing this dump one can find out the cause of the system hang. You can get a basic crash dump [...]
This is an advanced method to determine which disks we were booted from. I already posted a solution here, but it turned out to work only for PA-RISC systems. If you are on Itanium, it is more complicated. With adb on /stand/vmunix it only provides you the minor number of the disk in question. Since [...]
The latest 11.31 HP-UX version uses native multipathing with the help of the new IO stack. However if you’re on an older version, it was common along many customers to get a Powerpath license from EMC. It is to be used for building an active/active solution. Now here is a quick’n’short cheatsheet for the most [...]
This is from a recent HP-UX Customer Bulletin, Document ID: c02678348: The HP systems that use any version of VxFS file-system on HP-UX 11iv1, HP-UX 11iv2 and HP-UX 11iv3 operating systems and perform O_SYNC/O_DSYNC write I/O of any size that involves changes to a file size are impacted. This issue may be seen only if [...]
Hopefully everybody knows about the low quorum boot option, by which one is able to boot the system with a defective boot mirror. Now I will show you another boot option. The tunable maintenance mode is rarely used, but can be useful if you have misconfigured some kernel parameters and you have problems booting the [...]
If you’ve suspected something in the boot process and don’t want to continue with it, or it just seems to hang, you can press CTRL + / and it just stops and will give you a login prompt. I already mentioned this functionality in one of my earlier posts, but now I wanted to emphasize [...]
Not many people knows about the HP-UX tool ch_rc. This is a command line tool for people who are not so familiar with sed (stream editor), awk and pattern matching. SYNOPSIS /usr/sbin/ch_rc -a|-r|-l [-v] [-A] [-R root] [-p {parameter|parameter=value}...] [file...] If you want to query a variable in one of a config file under /etc/rc.config.d, [...]
By Viktor Balogh
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Also posted in HP-UX system administration, Languages and Scripting
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Tagged awk, boot, configuring, files, pattern matching, rc.config.d, scripting, sed, substitution, troubleshooting, variable
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