Configuration of AIX 5.3 on an IBM p5 55A server after installation

This document sets out the procedure to configure AIX 5.3 on an IBM P5 55A server connected to a DS4700 after installation

After AIX 5.3 is installed (see the AIX installation guide under the AIX and installation tabs on this website), there will be some configuration tasks necessary. The tasks documented here are not a complete and exhaustive list but some of the tasks I have needed to complete whilst installing servers.

Check if all necessary filesets are installed

If the new server is replacing an old server run lslpp -l | more on the old server and compare with the new server to ensure that all necessary filesets are installed

Check that rootvg is mirrored to the second internal hard drive

To do this type lsvg -l rootvg. You should see a list of the logical volumes in the volume group and twice the number of PPs to LPs, if this is the case then the LVs are mirrored. If there are the same number of PPs to LPs then there is no software mirroring. Also type lsvg -p rootvg to view the physical disks associated with that volume group.

There may be mirroring at the hardware/controller level, check if so before proceeding with configuring of software mirroring.

How to mirror the root volume group rootvg

Type mirrorvg rootvg

Once mirroring has finished type lsvg -l rootvg and you should see twice as many PPs as there are LPs

If for any reason you need to unmirror rootvg type rmlvcopy hd6 1 hdisk1 to remove the copy PPs on hdisk1 for LV hd6. Do this for each LV in rootvg

Increase the size of the rootvg logical volumes/filesystems if required

For instance to increase the size of /var to 800M type chfs -a size=800M /var

Increasing the size of the paging space

Paging space should normally be one to two times the size of memory depending on the application or database running on the server and also how much memory is installed in the server

To view the size and location of paging space type lsps -a

To view how many LPs are allocated to paging space type lslv hd6, hd6 with probably be the paging space LV

To increase the size of paging space by 64 logical partitions type chps -s64 hd6

Increasing the number of AIO servers

If oracle is going to be installed on the server (or another database that uses AIO) then you may need to increase the number of asynchronous I/O (AIO) server processes

To view the max and min number of AIO servers, type lsattr -El aio0

Oracle recommends minservers to be equal to the number of CPUs on the system or 10, whichever is lower

If you are using JFS/JFS2 Oracle recommends maxservers to be 10 times the number of logical disks divided by the number of CPUs.

For maxreqs set the initial value to 4 times the number of logical disks multiplied by the queue depth. You can determine the queue depth by running the following command: lsattr -E -l hdiskxx

To change the number of max and min servers type chdev -l aio0 -a maxservers='m' -a minservers='n'

To change the number of maxreqs type chdev -l aio0 -a maxreqs='n'

Setting the maximum number of processes per user (maxuproc)

To view the value of maxuproc type lsattr -D -l sys0 -a maxuproc

To change the value of maxuproc type chdev -l sys0 -a maxuproc='n', the new maxproc value takes effect after the next reboot

Creating files greater than 2GB

To be able to create files greater than 2GB on JFS filesystems (this option does not exist on JFS2) do the following

Start smit as root then select:

1. System storage management

2. File systems

3. Add/change/show/delete file systems

4. Journaled file systems

5. Change/show characteristics of a journaled file system (select File System where DB2 data resides)

6. Large file enabled TRUE

Also by default the value of fsize (file size) is set to 1048575 blocks (for JFS and JFS2)

To change this value to unlimited edit /etc/security/limits and change the value of fsize to -1. This can be done system wide by modifying the default value or per user by adding fsize = -1 to an individual user directive.

The value will take effect the next time you login

Configuration of RDAC (Redundant Dual Active Controller) multipathing

Ensure you have dual fibre channel HBA cards fitted in your server with a fibre cable from each card to a separate controller on your disk array. I used a DS4700 array for this configuration.

Run cfgmgr then type fget_config -A, you should get something similiar to the following if the correct filesets are installed



hdisk7 dac1

hdisk8 dac1

hdisk9 dac0

hdisk10 dac1

hdisk11 dac0

Including a -v as follows will include LUN information

fget_config -Av

Ensure that LVs and filesystems exist on the hdisks mapped out by the array before testing the multipathing failover. Once the filesystems are created and mounted test by unplugging one of the fibre cables from one of the HBA adapters. If filesystems don't exist on the hdisks then it will fail and the output of fget_config produces errors. If the failover works you should be able to cd into each filesystem and the output of fget_config should show only one dac in use, in this case either dac0 or dac1. Also on the DS4700 the LUNs that are on the controller with the disconnect fibre cable should move to the other controller, so all LUNs will be on either controller A or controller B

Configuring etherchannel bonding of ethernet ports

Before bonding the ethernet ports check that the characteristics of the ports to be bonded are correct, such as speed 10, 100 or 1000Mbs, full or half duplex and auto negotiation on or off.

To check the settings on en0 type entstat -d en0 or lsattr -R -l ent0 -a media_speed

To change the settings on en0 you will need to ensure that en0 is down and detached, to do this type

chdev -l en0 -a state=down then chdev -l en0 -a state=detach

Then to change the settings on en0 to 100 full duplex type chdev -l ent0 -a media_speed=100_Full_Duplex

NOTE you cannot do the following, chdev -l ent0 -a media_speed=1000_Full_Duplex, to change to 1000Mbps, this can only be set through auto negotiation as follows chdev -l ent0 -a media_speed="Auto_Negotiation" .

Then bring en0 back up as follows chdev -l en0 -a state=up

Once the characteristics are correct we can proceed to etherchannel bonding the ports together

Type smitty commodev, then move to EtherChannel / IEEE 802.3ad Link Aggregation

and then Add An EtherChannels / Link Aggregation

Select two ethernet adapters in this case ent0 and ent1 and hit return to create bonded adapter en2

To change the configuration to Active/Passive, go to the previous menu then go to

Change / Show Characteristics of an EtherChannel / Link Aggregation

Then change EtherChannel / link aggregation adpaters to ent0 only

And Backup adapter to ent1. Leave the rest as default and press return

Configure the bonded ethernet adapter en2 with an ip-address etc, as follows smitty mktcpip

Creating a RAID 10, mirrored stripe across 6 hdisks using LVM

Create a Volume Group VG and include all 6 disks, type smitty mkvg

Create one or more logical volumes in the volume group, type smitty mklv

Fill out all options as normal with the exception of the following parameters

Physical volume names choose all 6 hdisks

Range of physical volumes maximum

Maximum number of physical volumes to use for allocation should equal 6

Number of copies of each logical partition should be set to 2

To test if the correct LPs have been placed on the correct hdisks type lspv -p hdiskx where x should be replaced with each hdisk number