REV UP YOUR VIRTUAL ETHERNET There are a few strategies for speeding up communications between LPARs on the same physical server. One of those is using virtual adapters. Those virtual adapters can run at high speeds. You can turn on this turbo-charge feature by setting the MTU size to 65280 Bytes, which are actually SUPER jumbo frames, according to Wikipedia . Whatever that means, it sounds good, doesn't it? The transmission speed of Virtual Ethernet adapters is in the range of 1-3 Gigabits per second , depending on the... [More]

Tags:  adapter virtual io aix mtu ftp dd jumbo_frames chdev performance ethernet lsattr

Not a spitting image If you want to create a DVD image on AIX, you can do it right from the command line, without even touching physical media, using the mkdvd command. It was a wonder back in ... well, a long time ago ... when these new-fangled CDs came out and you could play music and use them as coffee cup holders (not at the same time). But the novelty of having a button on your computer that spits out a CD or DVD at you has somewhat faded. We want an image, but not a spitting image. On AIX you can create an ISO format image of a directory... [More]

Tags:  image dvd mkdvd iso chvopy vio virtual_media loadopt aix vios vmlibrary mksysb mkcd read_only

While you're in the middle of testing a new script, you may be tempted to add it to the cron to see how it goes. That involves: checking the system time using the date command translating that into the format explained by the man page for crontab : minute hour day_of_month month weekday command and setting the command just in time to start before the next minute ticks over. After reworking the script a few times, looking up the crontab command which tells you that the week starts with 0 for Sunday, and minutes come before hours, and not... [More]

Tags:  command regular crontab one-off at schedule script jobs cron aix

The AIX Virtual User Group continues its impressive lineup of speakers. This month Janel Barfield stepped through Partition Creation Settings . She covered plenty of aspects of the menus in the HMC where you create a logical partition, including the most misunderstood aspect of LPAR creation: Virtual Processors . Here are my rough transcripts of some important sections which were addressed. The first one comes in at about 19:40 into the presentation recording and deals with the concern many people have of assigning too many virtual processors... [More]

Tags:  creation entitled_capacity vp dlpar aix cpu virtual_user_group entitlement vps dynamic_lpar desired processor webinar maximum minimum virtual_processors lpar

If you're unfortunate enough to lose the root password on an AIX host, there is a way of recovering it . You can also recover the padmin password in VIOS if you've lost it. Basically, it's a matter of booting from AIX or VIOS installation media and stepping through the System Maintenance menus. When you do that, the boot file systems come from the installation media, and then you import the rootvg volume group which is on the original disks (the one with the unknown password). At that point you can run the passwd command or edit /etc/passwd.  ... [More]

Tags:  aix padmin password root

See update at end of post.  From the HMC, you can open a terminal session to the console of an LPAR. I reminisced about green screens and different console connections available to AIX in this post . But I didn't take account of one of them: you can create a virtual terminal session from the VIO Server to an LPAR. When you're logged in as padmin on the VIO Server you can create a terminal session using the mkvt command . mkvt command Purpose Create a virtual terminal connection to a partition. Syntax mkvt   {   -id   lparID } To terminate... [More]

Tags:  lpar padmin aix terminal_session hmc mkvt vio console modem

An IBM Oracle Technical Brief came out in May entitled Oracle Architecture and Tuning on AIX . There's a lot in it, but the good news is that if you're working on an AIX system that was a fresh install of AIX 6.1 or 7.1, then on the whole the default tuning parameters are what you need. If you're still on AIX 5.3, or if your system was migrated from AIX 5.3 to 6.1 to 7.1, you may need to revisit the tuning parameters. Do it anyway, if you can. There are two items which caught my eye especially from this Oracle Technical Brief: Logical Volume... [More]

Tags:  lv pp reorgvg agblksize disk_layout lvm tuning redo_logs striping performance oracle

 When you run some AIX Logical Volume Manager (LVM) commands, the volume group you're working on gets locked. Don't worry. The data is still accessible and users can work away merrily (or grumpily). The lock is put in place to stop other LVM commands which might try to update the same LVM metadata. For example, if you run migratepv to move your data to a new, fast-performing LUN (you hope), you might like to check the state of the volume group (VG). If you try to view the VG while it is locked, you'll get a message such as this: ... [More]

Tags:  volume_group_lock lslv 0516-1201 -l chvg locked lsvg error lspv lvm aix

What? A dump? AIX, like many other operating systems, provides the capability of making a system dump. This is nothing to do with the Windows Recycle bin or a Trash folder, a kind of holding place in case you want to undelete something. ("Undelete"? Who invented that word?). This IBM technote on Managing System Devices explains that you need a system dump which "automatically copies selected areas of kernel data to the primary dump device." Care factor zero? Now "automatically copying selected areas of kernel... [More]

Tags:  kernel support aix device sysdumpdev dumpcheck capture dump crash operating_system data system