Reminder: time to leave (and get a life)
One of the idiosyncrasies of software is the number of commands you have to to remember to exit. It could be exit , or quit , or bye , or logout , or ctrl-d , or maybe some other permutation. Imagine my horror, dear reader, when I sprang upon another exit command (or so I thought). The command is leave . But it's not exactly what you think. What leave does is simply send you a message reminding you to, well, log out (using exit / quit / logout / bye or ctrl-d ) and get away. It sounds like the sort of command you need when you are working back,... [More]
Tags: leave reminder |
Keep hd6 default paging space
There's nothing like running out of paging space to bring an AIX system to its knees, but I hit an unexpected paging space limitation today when I was trying to restore from a mksysb backup. I didn't run out of paging space - I didn't get the chance! When I tried restoring from a mksysb backup, I couldn't get past the initial bosinst menus. I hit this error: Error Warning image.data has
invalid logical volume data. Can not continue. To reboot the
system, press reset. >>> 1 Continue with Install In fact, the Continue with... [More]
Tags: hd6 swap install paging_space mksysb |
Novel uses for Name File Systems
You may know that WPARs use Name File Systems for creating alternate paths for rootvg file systems. Name File Systems have been around in AIX forever, and when you think about it, they can come in handy when you want to create a second view of a subdirectory. A Name File System is a pseudo-file system - a way of making a subdirectory its own dedicated mount with its own mount attributes such as cio, read-only etc.
Even if you don't use Name File Systems for that, here are some ideas of where an alternate path can be helpful. This is from my... [More]
Tags: namefs file-over-file_mount mount poweritpro |
efix available for HMC / SDMC Save Corruption Exposure
Following up on yesterday's post about HMC and SDMC code losing partition profiles , there's an efix available MH01263. This affects you if your HMC is running V7R7.3.0. From the efix README : This package includes the following fixes: Fixed a problem where managed systems lose profiles and profiles get corrupted resulting in Recovery state which prevent the ability to do DLPAR/LPM. Fixed a security vulnerability with the HMC help content. You should be able to obtain this efix from the IBM Support Portal , or try:... [More]
Tags: hmc sdmc |
Updated: HMC / SDMC Save Corruption Exposure
Update: there's an efix available for the HMC. For further details see this post . I received this notice today, which is very important if you're running HMC V7R7.3.0 or SDMC V6R7.3.0. The gist of it is that you could lose your partition profile data, so if you're already running these versions of the HMC or SDMC, you must backup your profile data and wait for a fix. And if you're on an older release of the HMC or SDMC, don't upgrade to these versions until a fix is released. I've included some links to the commands referred to in this... [More]
Tags: sdmc hmc |
Storage Parameters for MPIO on AIX
I came across this table in the Redbook Best Practices for DB2 on AIX 6.1 for POWER System .
It shows a list of the common parameters you need to look at for disks when they are connecting to a SAN. Tasks Actions to undertake Remarks For details see LUN creation on SAN storage box Create
LUN in particular RAID level Divide
LUN into desired capacity Map
to host group LUN creation on SAN
storage box Disks and HBA parameters Disks parameters: algorithm=round_robin
hcheck_interval=20
max_transfer=
reserve_policy=no_reserve
... [More]
Tags: attributes db2 storage san hcheck_interval hdisk max_transfer num_cmd_elems max_xfer_size tuning hba |
PP spreading and LV striping for Oracle
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 |
Could a vanilla VIOS installation be simplified?
If only a VIO server could be a VSCSI client ... A vanilla installation of the VIO server is very easy - once you can get
the LPAR to access the installation files. But that's the part which can be unnecessarily cumbersome and time consuming. Sure, you can use a physical Virtual I/O server installation DVD, but
that means getting the DVD to a data centre - and probably you with it.
Now if you're in a lab setting, or have a data centre across the floor from where you sit, that may not be any issue at all. But
for many of us, getting into... [More]
Tags: virtual_media_repository hmc installios install vscsi vios virtual_io_server virtual_media_library vanilla |
Recover root password and VIO server (padmin) password
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 |
AIX 7.1 troubleshooting documentation
I just came across the AIX 7.1 Troubleshooting documentation . It covers many solutions and problem-solving strategies on key topics. Like all official documentation, it has to cover some pretty obscure topics, too. But there are enough big ticket items to make it worth bookmarking. I've put in some of my comments to whet your appetite for further reading, or to spare you the trouble for topics on configurations which are not so common these days. Troubleshooting Find troubleshooting information located in the AIX® documentation library.... [More]
Tags: 7.1 aix troubleshooting |
AIX 5.4? Old Geek, new tricks
AIX 5.4? That's got to be a typo, right? I sprang upon two references to AIX 5.4 in official IBM documentation: The first is from the Performance Tools Guide and Reference : The information contained in this book pertains to systems running AIX 5.4 or later. Any content that is applicable to earlier releases will be noted as such. The second is from the documentation about Enhanced JFS (JFS2): Support for datasets has been integrated into JFS2 as part of AIX Version 5.4 . As I recall, AIX 5.4 was the name of the new release... [More]
Tags: jfs2 aix geek_party_tricks version_5.4 |
Parents and children: how to change mount points
If you need to move the entire contents of a file system, and the underlying storage doesn't need to change, you might as well just change the mount point. When you change the mount point of a file system, you effectively move all the files and directories that sail in it. Wouldn't it be wonderful if you could relocate your house and family just by slapping on a new sign on the gates of your city. In effect, that's what happens when you change the mount point. When you want to use a new mount point - effectively rename a file system's - it... [More]
Tags: aix mount_point chfs filesystem |
The inode I never knew
File contents and metadata When you change permissions on a file, the file contents aren't affected. The change is made to the i-node. So what's an inode? A quick visit to Wikipedia explains: "An inode stores all the information about a regular file , directory , or other file system object, except its data and name. " - inode, from Wikpedia All of that file "header" information is known as metadata. Here's how it is explained by the whitepaper, Inproving Database Performance with the AIX Concurrent I/O . My emphases... [More]
Tags: ls ctime file mtime lock aix istat inode find contents metadata |
AIX for smarties: what you ought to know (and probably already do)
Look how much you know! Here I want to highlight three AIX courses on offer, and emphasise the value of keeping up to date with what's happening in AIX and Power Systems. But this post is also to serve as an encouragement to the many people out there who keep the wheels turning and think they only have a basic grasp of AIX. You probably know a lot more than you let on. There are some excellent AIX training courses and seminars available from time to time. Even if you've been in the game of AIX for years, there'll be something you can learn. In... [More]
Tags: seminar training unix education ibm_systems_magazine aix_blogs webinar class course ibm_developerworks aix aix_articles |
You really ARE just a number!
I hate to break it to you, but to AIX (and other Unix platforms), your identity as a user boils down to this: 204 (or some other User ID). Sure, you have a meaningful user name (provided your parents didn't call you DEFAULT or ALL, or put question marks in your name - the mkuser command explains the rules) but did you really think AIX stores a name like johnathon_doe_junior on every file little Johnny owns? NO WAY! What computers think of us Here's how it all works. If you run ls -l you see your file permissions, including the name of the owner... [More]
Tags: long_username uid istat group metadata chown ls aix mkuser file_owner gid just_a_number i-node |
UPDATE: Hoarders and chuckers (Reconstructing a VG)
It's pretty easy to move a volume group from one AIX system to another. You unmount all the file systems from the source volume group, varyoff the VG, export the volume group ( exportvg ), and then remove the disks from the source system ( rmdev -dl hdisk N ). Then you assign the LUNs to the target host, import the volume group , mount the file systems, and check permissions. But what if you want to copy a volume group? You might want to replicate a volume group, by doing a flash copy across the SAN. Then on the remote site, you'd present the... [More]
Tags: physical_volume varyoffvg recreatevg varyonvg migration volume_group importvg pv file_system disk exportvg aix lun flash_copy |
Quicker than editing /etc/hosts (not suitable for younger readers)
What's the quickest way to add an entry to /etc/hosts? edit the file vi /etc/hosts append to /etc/hosts from the command line: echo "192.168.2.5 mynewhost" >> /etc/hosts add the host via SMIT , or use the hostent command. The hostent command is actually the quickest way. Simple syntax To Add an Address-to-Host Name Mapping with the hostent command, here's the syntax: hostent
-a IPAddress -h hostname Those flags are easy enough to remember: -a is to add an IP address -h is the hostname hostent
-a 192.168.2.5 -h mynewhost The... [More]
Tags: epoch unix /etc/hosts hostent vi hostname aix |
Too many Virtual Processors?
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 |
SDMC brings new terminology for LPARs, Servers, Partition mobility
Rob McNelly in this week's AIXchange blog spoke of the IBM Systems Director Management Console (SDMC). This is the successor to the Hardware Management Console (HMC) and the Integrated Virtualization Manager (IVM), and shows how IBM Systems Director is going to take an increasingly important role for administrators. Replace groan with grin I understand that the take up of Systems Director in the AIX world hasn't been that strong. Many people have had bad experiences, especailly with earlier versions and learning to navigate the Director... [More]
Tags: director aix frame power lpar sdmc server virtual_server logical_partition partition |
VIOS: Insufficient memory, not able to complete the command
A strange "insufficient memory" error on the VIO server took a little bit of untangling. The error occurred when I logged into the VIO server command line as padmin shortly after running a backup. I was attempting to display the Virtual Media Library* contents. When I entered the lsrep command , it reported the following error: Insufficient memory, not able to complete command. I tried to list the virtual resources using the HMC GUI ( Server > Virtual Resources > Virtual Storage Management ) but it seemed to take an eternity. It... [More]
Tags: virtual_media_repository lsrep aix storage_pool vios virtual_media_library mount rootvg mkrep unmount insufficient_memory vmlibrary |
Helpful editing tips within SMIT screens
Many people love using SMIT but find its editing functionality a little cumbersome. So here are some editinig tips you should find useful, and you may not have been aware of: If you want to wipe out the value you have entered, you can delete to the end of the field by using Ctrl-k (that's holding down the Ctrl key and pressing the k ). To delete a single character, use Ctrl-x . To go down a page at a time, press Ctrl-v To go up a page, use Esc-v . The tab key allows you to toggle through true / false fields such as yes / no fields or some... [More]
Tags: ctrl-k esc-v edit smit aix smitty ctrl-v ctrl-x |
Speed up recovery with JFS2 Filesystem NOLOG feature
IBM recently issued a Technote explaining the very handy NOLOG option which you can use when mounting JFS2 (also known as Enhanced Journaled File Systems). The NOLOG feature was added in AIX 6.1 and it only applies to JFS2, not to the older JFS. If you need to copy or restore data to a file system in a hurry, then
you could mount the target file system with the NOLOG option. This was one of three suggestions I made in an earlier post for when you need to copy data quickly, but the Technote covers the NOLOG more comprehensively than I did in... [More]
Tags: logical_volume file_system nolog performance recovery restore aix fast_write mount enhanced_journaled_file_s... jfs 6.1 jfs2 inline |
Bypass the volume group lock
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 lsvg locked error lspv aix lvm |
Webinar: Advanced Management Features for the HMC - Part 2
Joe Armstrong from the AIX Virtual User Group has arranged a follow up webinar on the Advanced Management Features for the HMC. You can find part 1 of this presentation on the AIX Virtual User Group wiki, but here's what Joe Armstrong advises about part II: Last
month we ran out of time while Allyn was presenting on HMC Advanced
Management Features, so we are continuing that discussion this week.
This will include maintenance and upgrades, best practices for
managing the HMC, and features added to the HMC to support new
functions of the... [More]
Tags: asmi hmc virtual_user_group upgrade best_practices aix hardware_management_conso... firmware maintenance power7 power6 |
Method error when changing vscsi path
Recently I tried to run the chpath command to set the priority on a VSCSI disk. Here's the command I ran: chpath -l hdisk4 -p vscsi1 -a priority=2 And here's the unfortunate error I hit: Method error (/etc/methods/chgdisk): 0514-080 Invalid routine argument
detected. Madness in the method No matter
how long I work on AIX, I never get excited when I get a "Method
error". Fortunately, this one was very easy to fix. I was simply missing a VSCSI map on the VIO server. A little
bit of background will help explain the... [More]
Tags: vio_server chpath aix virtual method_error padmin mpio vscsi vios chdev lspath |
Understanding fileset numbering
When you list filesets with the lslpp -l command, you get output such as this: devices.common.IBM.storfwork.rte 6.1.6.1 COMMITTED Storage Framework Module devices.common.IBM.usb.rte 6.1.6.0 COMMITTED USB System Software The second field (highlighted) shows the numbering of the fileset. The IBM AIX Operating System Release and Service Strategy Details and Best Practices explains what that means. In the section "Changing the M in VMRF", it says: Starting with AIX 5.3 TL7, any filesets that are updated will get a new ‘M’ in the VRMF.... [More]
Tags: tl documentation fileset version technology_level aix_version release aix service_pack lslpp oslevel patch fix sp |
New file system, old logical volume
The Oracle DBAs asked for the redo logs file system to have a new agblksize. I recall that Jaqui Lynch recommended this in her 2008 article In Tune with Oracle : Redo logs and control files should be in their own file system with an agblksize set to 512. The I/O size is always a multiple of 512 and you’ll do unnecessary I/O if you leave it at the default of 4096. The other file systems can be left at the default with the exception of the database (DBF) files. A new file system Changing the agblksize meant recreating the file system. Ordinarily,... [More]
Tags: fs chfs logical_volume_manager lslv file_system lv aix lvm |
Advanced HMC Management Features
Technical presentations for techos The AIX Virtual User Group - USA presents excellent courses each month on AIX and aspects of managing Power Systems. These are technical presentations without the marketing fluff. This month was on the Advanced HMC Management Features. There was a wealth of material covering all sorts of aspects of the HMC, including: LPAR Wizard overview Setting up redundant HMCs Managing HMC Updates and Upgrades (including the upgrading over the network) Backup and recovery scenarios Integrated Virtual Ethernet (IVE) and how... [More]
Tags: hardware_management_conso... virtual_fibre_channel firmware npiv ive vug integrated_virtual_ethern... hea data_replication aix backup critical_console_backup virtual_user_group system_firmware hmc save_upgrade_data recovery dual_hmc host_ethernet_adapter |
Looking good Down Under
With the new look and feel of developerWorks the team at AIX Down Under voted unanimously to update the layout of this blog. The new blog theme comes from a new blog template developed by Bob Leah , developerWorks Chief Design Strategist. Some of the features which you might see turning up are: thumbnail and preview, so that you don't have to suffer when I write my posts with -verbose turned on widgets for Twitter, Facebook Like, Digg, Delicious (if you don't know what they are, ask your grandchildren) popular tags previous and next post... [More]
Tags: aix_down_under bob_leah blog template developerworks aix |
Ready for AIX recovery with mksysb and mkdvd
mksysb - an oldie but a goodie Long before the days of HMCs, VIO servers and LPARs, AIX version 3 and 4 ran on standalone systems. A system had its own tape drive. This would be useful for mksysb backups, which backed up the rootvg. Reliability, Availability, Scalability 1990s style Actually, a rootvg backup was usually a full backup of everything - including all the data - since the idea of separate disks and volume group for data was a luxury most of us hadn't thought of. I saw many sites which survived for 10 years on a single 1 GB SCSI... [More]
Tags: iso media mkdvd restore mksysb nim dvd backup virtual aix library vmlibrary virtual_optical_device rootvg repository |
Anthony English is an independent contractor who solves expensive problems for businesses running IBM Power Systems.
He has written extensively about AIX and has been recognised for his contributions and thought leadership by being named an IBM Champion for Power Systems.
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