Restarting VIO Server Logical Partition

Before the admin shutdown VIO server LPAR, admin must remember the following points:

1. If client LPAR uses storage and networking virtual resources provided by VIO server then admin must deactivate the LPAR and then shutdown the client LPAR.
2. Each shared memory partition must be a shutdown because every partition accesses its paging space device using VIO server LPAR that the admin is planning to shutdown.

To restart VIO server from HMC:

1. Expand system management -> servers
2. Click managed systems on which LPAR is located
3. Select LPAR
4. Click Operations -> Restart
5. Click OK

And now complete the following task:

1. Activate client LPAR
2. Activate each shared memory partition that accesses paging space device using VIO server LPAR that is restarted.

P.S: Please refer the redhat IBM pdfs for detailed understanding!

Happy Learning!

Default (Standard) File Systems

Default (Standard) File Systems:

Default AIX file system during OS installation:

/ – 1GB

/usr – 4 GB

/var – 4GB

/tmp – 4GB

/opt – 1GB

/home – 1GB

Paging Space:

1. Ideally, paging space should be double the ram size

2. If RAM >= 256MB then PS should be 512MB

3. If RAM < 256MG then PS is twice of RAM

4. If RAM is 8GB paging space should be 16GB

5. Only 1 PS per disk

6. Use disk with least activity for paging space

7. Do not extend PS to multiple PV

8. Paging Space should be backed by hardware redundancy technology

9. Should not delete system’s default paging space on hd6

10. Should not reduce size of hd6 below 32MB. Should not be less than 64MB for AIX 4.3 and above

11. Paging Space should not take more than 20% of disk space

12. Divide paging space into multiple PS for greater flexibility

13. /etc/swapspaces contains list of PS that is activated at system start-up

Introduction to NMON

NMON monitors and analyse performance of operating system. It is available in AIX and Linux.

NMON monitors:

1. CPU Usage
2. Memory Usage
3. Free space on file system
4. Top processes
5. http webcache
6. paging space
7. network adapters
8. disk adapters
9. network i/o rates

All this is easily monitored by NMON.

Happy Learning!

Additional Information On AIX System Administration – IV

# lsfs command gives the following output:

Hd1 – home

Hd2 – USR

HD3 – TMP

HD4 – Root

HD5 – BLV

HD6 – Paging Space (2 types: primary, secondary)

HD7 – Not Found

HD8 – JFS

HD9 – VAR

HD10 – MNT

HD11 – admin (available in AIX V 6.1)

LED code 0c0 means successful completion of dump.

To view extended permissions, command used is:

# ls –e <filename>

Command used to set tty port for bidirectional mode:

# share <port attributes>

Commands used to setup quota for file system for end users are:

# vi /etc/<file system>

# edquota /<file system> <username>

# quotaon <file system>

# quotaon /<file system>

To initiate system dump, command used is:

# sysdumpstart –P (for primary)

# sysdumpstart –S (for secondary)

SNAP is generally used to gather system information.

Some of the SNAP commands are:

# snap –a

# snap –g

# snap –D

Image.data contains information about VG’s and LV’s.

Bosinst.data contains information about installation flow control.

To view mksysb tape and to restore particular file from mksysb tape, commands used are:

# tctl –f /dev/<tape drive name>

# restore –tvf /dev/<tape drive name>

# restore –xvf /dev/<tape drive name>

For eg:

# tctl –f /dev/rmt0

# restore – tvf /dev/rmt0

# restore – xvf /dev/rmt0

Tctl command is basically used to rewind the tape drive.

To list NIM objects, command used:

# lsnim

NIM stands for network installation management.

To see NIM log, command used is:

# nim –o showlog –a full_log = yes –a log_type = logtype NIMclient

Logtype can be boot, script etc.

NIMClient is the hostname / ip address of the client machine.

Sources of this command : IBM AIX Forum

# smit system command is used to change the server time.

# smit date command is used to change system date.

Time synchronization is either done by running time demon or ntp demon.

P5 family:

1. Entry :

i.      P5 510

ii.      P5 520

iii.      P5 550

1. Mind Range :

i.      P5 570

1. High End :

i.      P5 575

ii.      P5 590

iii.      P5 595

Physical Volume (PV) id can be found in Cuat ODM class.

Device in defined state means there is an entry in ODM class CuDV.

Procedure to change bootlist from hdisk0 to hdisk1:

Go to SMS mode by pressing F1 and change the bootlist by running the following command:

# bootlist –m normal hdisk0 hdisk1

If a machine keeps rebooting and repeating POST, it means either there is invalid bootlist or corrupted BLV or hardware failure of boot device.

More we will discuss about AIX System Administration in the coming posts.

Till then,

Happy Learning !

Additional Information On AIX System Administration – I

This post will discuss about some additional information about AIX OS that can be used in production environment.

If the admin wants to filescan the root file system:

• Admin must go into the maintenance mode after booting from the disk.
• Type the following command:
• # /etc/continue <bootdisk> exit
• For eg:
• # /etc/continue hdisk0 exit
• # fsck /dev/hd4

To filescan the /usr directory:

• To do this, /usr should be unmounted. Unmounting is not an easy process as /bin directory is linked to /usr directory in /usr/bin. So admin must go into the maintenance mode first and then run
• # getrootfs <bootdisk> sh
• For eg:
• # getrootfs hdisk0 sh
• After running this command, next command user needs to run is:
• # fsck /dev/hd2

To change the parameters (for eg: number of processes per user run), command used is:

• # lsattr –EH –l sys0 –a maxuproc
• # chdev –EH –l sys0 –a maxuproc = 200

To list all the virtual printers a print queue is using, command used is:

• # lsvirprt

To check if AIX has a PTF applied to it or not, command used is:

• # lslpp –B1 UXXXXXXX
• Where
• UXXXXXXX is the PTF number

PTF stands for program temporary fix.

Click cancel or F10 to exit from SMIT menu.

To check inode statistics, command used is:

• # istat /etc/passwd

Various degraf commands are:

• # defrag –q

Or

• # defrag –r

Or

• # defrag –s

Alog information is available in /var/adm/ras directory.

• # smit alog_show
• Command can also be used for the same output on smit screen as that of alog command.

Fileset Revision Level Identification (FRLI)

• XX.XX.XXXX.XXXX
• XX stands for Version (0-2)
• XX stands for release (0-2)
• XXXX stands for modification (1-4)
• XXXX stands for Fix level (1-4)
• # smit update_all command can also be used for modification and fix level information.

JFS stands for journeled file system.

File system:

• Hd1 : Home
• Hd2 : USR
• Hd3 : TMP
• Hd4 : ROOT
• Hd5 : BLV
• Hd6 : Paging Space
• Hd7 : Not Found
• Hd8 : JFS / JFS2
• Hd9 : VAR
• Hd10 : OPT

Happy Learning!

Different Commands For Paging Space Administration

This post will talk about various commands involved to carry out paging space administration.

The first and foremost command always used is to check the already available paging space present in the server. To list all the paging spaces, command used is:

# lsps –a

But if admin wants to check summary of all the paging spaces available, to list summary, command used is:

# lsps –s

To create a new paging space:

# mkps –s <number of LPs> <vgname>

For eg:

# mkps –s 10 oracle_vg

This will create a paging space with default name for eg: paging01

Once created, admin can verify the same by running the command to list paging space once again,

# lsps –a

To activate the paging space:

# swapon /dev/paging01

To extend paging space:

# chps –s <number of LPs to be added> <paging space name>

For eg:

# chps –s 10 paging01

This will add additional 10 LPs to paging01.

To reduce the number of LPs from a paging space, command used is:

# cjps –d <number of LPs to be reduced> <paging space name>

For eg:

# chps –d 10 paging01

All the commands admin execute can verify the result by running the command to list the paging space:

# lsps –a

To deactivate the paging space:

# swapoff /dev/paging01

To completely remove the paging space, first admin needs to deactivate it and then run the command to remove it:

# rmps paging01

Command to activate all the paging space listed:

# swapon –a

OR

# swap –activate

Command to deactivate all the paging space listed:

# swap –deactivate

All the paging space is defined in /etc/swapspaces.

Can be checked by running the following command:

# Cat /etc/swapspaces

With this post, I covered nearly all the topics to understand the basics of LVM.

I hope you find the blog till date interesting and worth reading.

Happy Learning till then!

Paging Space Administration

What is Paging Space?

What is Page-in & Page-out?

What is thrashing?

All these questions about paging space will be answered in this very particular post.

What is Paging Space?

In a system, there are multiple processes running. For a new process to be actively running, the process should be loaded into the OS memory. Once the process is loaded, it is then assigned number of 4 KB units called page frames.

Keeping this in view, more number of additional processes is loaded into the memory with each process assigned 4 KB areas. But when the processes are overloaded and the memory is full, OS scans memory to trace frames that are least recently used. When such a frame is discovered, 4 KB block or page of disk space is allocated and the data from least active frame is moved to area on the disk. This area on disk is called Paging Space.

What is Page-in & Page-out?

If the paged out information for the least active process is needed back into the memory, the page is retrieved from the disk and brought back into the memory. This is called page-in.

Similarly, when the least active frame is moved out from the memory on to the disk, the process is called page-out.

What is thrashing?

If the OS is loaded with many active processes and there is no further real memory available to load additional active processes, the OS goes into the constant state of paging called thrashing as no additional real memory is available to load a new process into the memory.

Increasing the amount of paging Space will be of no benefit because the processes involved are all active and thrashing is the result of not enough real memory.

Next post will discuss about the various Paging Space Administration commands.

Till then,

Happy Learning !

P.S: This post is written from various online sources like IBM Red Hat Books, pd’fs and other online content!