asr.tech.notes

Disable GRO for a ethernet interface

2012-06-18T16:40:00.001-07:00

Use this to disable the GRO (Generic Receive Offload) on a RHEL system:

# /sbin/ethtool -K eth4 gro off

You can also add this to the /etc/rc.local file to persist across restarts.

There are also other options you can set with the ethtool utility. Please see the man page for ethtool for more information

Configure default MTA on Red Hat Enterprise Linux

2012-06-12T11:32:00.001-07:00

1. Install postfix
# yum install postfix
2. Stop and Disable sendmail (if running)
# service sendmail stop
# chkconfig sendmail off
3. Enable and start postfix
# chkconfig postfix on
# service postfix start
4. Update postfix config with correct relay host
# postconf -e relayhost=yoursmtphost.com

5. Make postfix the default MTA

# alternatives –config mta

There are 2 programs which provide 'mta'.

Selection Command

-----------------------------------------------

*+ 1 /usr/sbin/sendmail.sendmail

2 /usr/sbin/sendmail.postfix

Enter to keep the current selection[+], or type selection number: 2

5. Test mail relay
# echo TEST | mail -s TEST youremail@yoursmtphost.com

HP-UX tape configuration

2012-06-11T15:32:00.001-07:00

Here are few commands to configure tape drives in HP-UX
1. Scan for new devices:
# ioscan –fnC tape
2. List tape drives currently recognized by the OS (without performing an actual hardware scan)
# ioscan –fnkC tape
3. remove all the special files used by the tape drives
# rmsf /dev/rmt/*
4. Recreate the specil files for the tape drives
# insf –C tape –e
5. Remove a tape drive (that has a NO_HW state)
# rmsf –H 0/7/1/0.1.24.255.5.5.0

Find the WWN for the HBAs:

# ioscan –fnkC fc

# fcmsutil /dev/fcd0

Find the WWN for the tape drives connected to the HBA:

# fcmsutil /dev/fcd0 get remote all

**These are just a handful of commands to deal with the tape drives. Not to be used as a procedure

Create file system from Command line (AIX)

2011-12-19T17:33:00.001-08:00

1. Create a Volume Group (Scalable):

# mkvg -S –y ‘vgname’ –f hdisk12

2. Create a LV in the VG (jfs2):

# mklv –y ‘lvname’ –t jfs2 vgname 1024

3. Create a file system on the previously created LV (jfs2):

# crfs –v jfs2 –d ‘lvname’ –A yes –p rw –m ‘mount point’ –u ‘mount group’

Dig that!

2011-09-28T13:43:00.001-07:00

Here are some handy ‘dig’ commands to verify DNS records:

Do a hostname lookup

# dig www.google.com

; <<>> DiG 9.4.1 <<>> www.google.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 76
;; flags: qr rd ra; QUERY: 1, ANSWER: 7, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.google.com. IN A

;; ANSWER SECTION:
www.google.com.         84790   IN      CNAME   www.l.google.com.
www.l.google.com.       259     IN      A       209.85.148.104
www.l.google.com.       259     IN      A       209.85.148.105
www.l.google.com.       259     IN      A       209.85.148.106
www.l.google.com.       259     IN      A       209.85.148.147
www.l.google.com.       259     IN      A       209.85.148.99
www.l.google.com.       259     IN      A       209.85.148.103

;; Query time: 119 msec
;; SERVER: 10.0.0.8#53(10.0.0.8)
;; WHEN: Wed Sep 28 13:23:41 2011
;; MSG SIZE rcvd: 148

Get a short answer

# dig www.google.com +short

www.l.google.com.
209.85.148.99
209.85.148.103
209.85.148.104
209.85.148.105
209.85.148.106
209.85.148.147

Get just the answer section

# dig www.google.com +noall +answer

www.google.com.         84278   IN      CNAME   www.l.google.com.
www.l.google.com.       49      IN      A       209.85.148.105
www.l.google.com.       49      IN      A       209.85.148.106
www.l.google.com.       49      IN      A       209.85.148.147
www.l.google.com.       49      IN      A       209.85.148.99
www.l.google.com.       49      IN      A       209.85.148.103
www.l.google.com.       49      IN      A       209.85.148.104

Do a reverse lookup

# dig -x 209.85.148.105 +noall +answer

105.148.85.209.in-addr.arpa. 45351 IN PTR fra07s07-in-f105.1e100.net.

Use your ‘search’ string from the /etc/resolv.conf

#dig www.google.com +search

Reference:

http://www.madboa.com/geek/dig/

http://linux.die.net/man/1/dig

Red Hat Enterprise Linux 6 – How to: migrate data to a new Physical Volume and remove the old PV

2011-09-14T13:42:00.001-07:00

Add new devices to the system. Use rescan-scsi-bus.sh to scan for new devices or restart the system to get the new devices
Create LVM Physical Volumes with the new devices

# pvcreate /dev/sdxx

Add the devices to the respective VGs

# vgextend vgname /dev/sdxx

Migrate the data from the existing PV to the new PV

# pvmove /dev/sdxx

o Where /dev/sdxx is the existing PV that needs to be removed from the VG

List the PVs to make sure the PV that needs to be removed has no data on it

# pvs –o+pv_used

PV VG Fmt Attr PSize PFree Used
/dev/sda2 rootvg lvm2 a- 39.51g 8.63g 30.88g
/dev/sda log2vg   lvm2 a- 30.00g 8.00g 0
/dev/sde log2vg   lvm2 a- 30.00g 8.00g 22.00g
/dev/sdf datavg   lvm2 a- 100.00g 5.00g 95.00g
/dev/sdg log1vg   lvm2 a- 30.00g 8.00g 22.00g
In the above example, the data was moved from /dev/sda to /dev/sde (they reside in the same VG)

Remove the PV from the VG

# vgreduce vgname /dev/sdxx

Remove LVM PV information from the device

# pvremove /dev/sdxx

Delete the device from system

# echo 1 > /sys/block/sdx/device/delete
Or use rescan-scsi-bus.sh to remove the device

Converting SEA on VIO from access to trunk mode

2011-09-12T17:19:00.001-07:00

Shared Ethernet Adapters on VIO server can be configured in two different modes while accessing the external network.

1. Simple mode

2. Trunk mode or 802.1Q mode

In a Simple mode, the SEA is not aware of any VLAN information and bridges all the network packets to the external switch. the external switch then determines the target and routes/discards it accordingly. This is very useful when there is only one VLAN that needs to be serviced through the SEA to the LPARs using these VIO servers. The configuration on the switch as well as the VIO (SEA) is simple and straight forward.

In a Trunk mode (802.1Q complaint), the SEA is aware of the VLANs and bridges only the packets that is part of the ‘Additional VLANs’ list. The external switch then determines the target and routes/discards it accordingly. This is very useful when there is a need to service multiple VLANs through the same SEA adapter. This will provide the ability to create LPARS from multiple networks to reside on the same physical nodes. This requires additional configuration on the switch as well as the VIO servers.

The configuration part of the SEA on the VIO are discussed here

This post will discuss the steps needed to convert a SEA from simple mode to a trunk mode. The following is the current set up assumed on this post:

Hardware – Power 7

VIO Servers – Dual

VIO Server IOS Level: 2.1.2.13-FP-22.1 SP-02

HMC Version: Version 7, Release 7.2.0, SP2

SEA – Simple mode

The ports on the external network switches are configured as ‘Access Port’ (cisco term) with allowed VLAN set to 22

Ethernet Adapters used (on both the VIO Servers)

ent2 – Physical Ethernet Adapter on each VIO Servers (P2-C1-T1)

ent0 – Virtual Ethernet Adapter that will act as the bridge to the external network (PVID – 1002) (V1-C10-T1)

ent1 – Virtual Ethernet Adapter used for control Channel (V1-C11-T1)

ent3 – Virtual Ethernet Adapter used for VIO Server’s management interface (V1-C12-T1)

ent4 – SEA created with ent0 and ent1

All the LPARs under these VIO Servers have the Virtual Ethernet configured to use 1002 as their PVID

Steps to convert this setup to a trunk mode:

Shutdown all the LPARs (except the VIO servers)
Login to the VIO Servers through a console from the HMC
Change the network ports on the external switch as Trunk port with required VLANs (22)
Shutdown one of the VIO servers (vio2 for instance). This is to avoid any possible network issues while reconfiguring one of the VIO servers
From the HMC, uncheck ‘Access external network’ from the current Virtual Ethernet that is configured as the bridge (Adapter ID 10)
From the HMC, add a new Virtual Ethernet Adapter to the VIO Server (vio1) – configure it to

Enable ‘Access external network ‘

Enable ‘IEEE 802.1q compatible’

Add ‘Additional VLAN IDs to 22’

Set Trunk Priority to 1 (2 for the other VIO Server)

Shutdown and Activate the VIO Server if the virtual Ethernet was not added with DLPAR. Restarting the VIO Server will not bring in the changes made on the profile. A complete shutdown and activation of the profile is needed
This should create a new adapter ent5 on the VIO Server (V1-C13-T1)
Reconfigure the SEA to use the new virtual Ethernet Adapter as the bridge. You can leave the current virtual Ethernet as part of the SEA’s virtual adapter list if there are some LPARS that would need it to communicate internally.

# chdev –dev ent4 –attr virt_adapters=ent5 pvid_adapter=ent5

Restart the VIO server
The VIO Server should be available on the network now through ent3
This will convert the SEA to use 802.1q compatible adapter as the network bridge to the external network

Shutdown this VIO Server and execute the similar procedure on the other VIO Server (vio2). Once VIO2 has been successfully converted, bring up VIO1 as well.

From the HMC, change the PVID for all the LPARs to use 22 and activate the saved profile for each LPAR.

At this point all the LPARs will be communicating to the external network using the new 802.1Q compatible adapter.

Red Hat SELinux–How to Enable/Disable

2011-08-11T14:19:00.001-07:00

Here is the quick how-to for enabling and disabling SELinux on a Red Hat Enterprise Linux server temporarily and permanently.

There are 3 modes available with the SELinux-

Enforcing – SELinux policy is enforced and access is denied based on the SELinux policy rules.

Permissive – SELinux policy is not enforced. Access is is not denied, but what would have been denied if it were enforced will be logged.

Disabled – SELinux is disabled completely. only DAC rules are used.

To permanently disable SELinux on the system, update ‘SELINUX=disabled’ in /etc/selinux/config file and reboot the system for the change to take effect

To change between the modes temporarily during run time, use the /usr/sbin/setenforce command with the appropriate mode

/usr/sbin/setenforce 1 will set the mode to Enforced

/usr/sbin/setenforce 0 will set the mode to Permissive

/usr/sbin/getenforce to display the current mode

Refer RHEL 6 SELinux guide for more detailed information

http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/pdf/Security-Enhanced_Linux/Red_Hat_Enterprise_Linux-6-Security-Enhanced_Linux-en-US.pdf

Red Hat Linux Crash Dump Analysis

2011-08-02T14:23:00.001-07:00

Some useful links for analyzing Crash Dumps:

Quick overview of Kernel Crash Dump Analysis

http://magazine.redhat.com/2007/08/15/a-quick-overview-of-linux-kernel-crash-dump-analysis/

Crash Facility – White paper

http://people.redhat.com/anderson/crash_whitepaper/

More about Oops messages:

http://lxr.linux.no/linux/Documentation/oops-tracing.txt

How to resize root file system on RHEL 6

2011-07-25T13:08:00.001-07:00

Here is the list of steps to reduce the root file system (lv_root) on a RHEL 6 Linux server:

Boot the system into rescue mode. Do not mount the file systems (select the option to 'Skip' in the rescue mode and start a shell)
Bring the Volume Group online

#lvm vgchange -a -y

Run fsck on the FS

#e2fsck -f /dev/vg_myhost/lv_root

Resize the file system with new size

#resize2fs -f /dev/vg_myhost/lv_root 20G

Reduce the Logical Volume of the FS with the new size

#lvreduce -L20G /dev/vg_myhost/lv_root

Run fsck to make sure the FS is still ok

#e2fsck -f /dev/vg_myhost/lv_root

Optionally mount the file system in the rescue mode

#mkdir -p /mnt/sysimage/root
#mount -t ext4 /dev/mapper/vg_myhost-lv_root /mnt/sysimage/root
#cd /mnt/sysimage/root

Unmount the FS

#cd
#umount /mnt/sysimage/root

Exit rescue mode and boot the system from the hard disk

#exit

Select the reboot option from the recue mode

VIO Server–Performance and sizing considerations

2011-06-24T13:56:00.001-07:00

http://www14.software.ibm.com/webapp/set2/sas/f/vios/documentation/perf.html

Reproduced from the link posted above:

The VIOS online pubs in InfoCenter include sections on sizing for both Virtual SCSI and SEA.
http://publib.boulder.ibm.com/infocenter/eserver/v1r2s/en_US/index.htm

For Virtual SCSI, please see the section titled "Virtual SCSI Sizing Considerations". For SEA, please see the section titled "Planning for shared Ethernet adapters."

QOS considerations

The Virtual I/O server is a shared resource that can be shared concurrently by Virtual SCSI and by Virtual Ethernet / Shared Ethernet.

Depending on the specific configuration of a Virtual I/O server, quality of service issues (long response times) may be encountered if insufficient CPU resources exist on the I/O server partition for the I/O load required. Recommendations for sizing and tuning the Virtual I/O server are discussed in the following paragraphs.

The Virtual Ethernet and Shared Ethernet drivers (LAN environment), like most device drivers, typically drive high interrupt rates and are CPU intensive. Streaming large packet workloads, like file transfers or data backup/restore, requires lower interrupt load than do other workloads that generate a lot of small packets. The Virtual SCSI has similar characteristics, where large IO's require lower CPU interrupt rates than do small I/O's. The Virtual SCSI environment runs at low priority interrupt levels, while the LAN environment runs on high priority interrupts. Because LAN's can be driven to high rates of activity with relatively little hardware and LAN pacing of requests for throughput requires matching adapter speeds, the LAN runs with high interrupt priority compared to disks which tend to be paced by disk latency.

If the combined workload of the LAN and SCSI in an I/O server partition are such that the available CPU capacity of the I/O server partition becomes expended, the response times will increase and the quality of service will be reduced, with the Virtual SCSI workloads being impacted the most. The possible tuning options are discussed below.

Proper sizing of the Virtual I/O server
Threading or non-threading of the Shared Ethernet
Separate micro-partitions for the Virtual I/O server

The Shared Ethernet environment requires about 63% of a single CPU Virtual I/O server for simplex streaming of data or about 80% of a CPU for full duplex (two direction) streaming of data over a single Shared Ethernet adapter and one Virtual Ethernet. The Virtual SCSI requires about 20% of a CPU for large block streaming or as much as 70% for small block, high transaction rate workloads for a dual disk adapter environment. Given normal workloads, a single shared Gigabit Ethernet and single disk adapter can coexist on a dedicated partition utilizing a single CPU server without processor capacity limitations. If dual Gigabit Ethernets were to be configured on the same system, then the processing cycles can be totally consumed by the LAN environment and the disk response time may become poor at high processing utilization. The simplest solution is to configure a second CPU into the partition to provide the CPU resources needed to process the workload.

Another option is to tune the I/O server based on the workload and hardware configuration. One tuning variable is a "threading" option on the Shared Ethernet. Without threading enabled, the Virtual Ethernet and the real Ethernet drivers run on the interrupt level and forward their incoming packets thru the shared Ethernet driver and the destination driver on the interrupt level. This is the most efficient in terms of CPU cycles consumed (minimum path length) but is also the most disruptive for the SCSI software that runs more at a lower interrupt level. Threading can be enabled on a per Shared Ethernet device basis. Threading will cause the incoming packets to be queued to a thread. One of 10 special threads in the kernel will then be dispatched and will process the packet in the shared Ethernet driver and the associated outbound driver. This puts more processing in a user thread context and allows this processing to be shared more equally with the virtual SCSI I/O. However, the threading does increase the total CPU cycles required by the LAN (longer path length). The trade-off is more consistent quality of service but at a lower overall LAN throughput.

APAR IY62264 changes the default behavior of the Shared Ethernet devices to have "threading" enabled. Prior to this APAR, the default was non-threaded.

Depending on the customer environment, the threading option on Shared Ethernet can be tuned to help provide higher LAN performance (non-threaded) or improved shared performance when running with Virtual SCSI by running threaded. The following table shows example CPU utilization and throughput rates for the Virtual I/O server running one shared Ethernet with one Gigabit Ethernet and one Virtual Ethernet with and without threading.

P5, L4 (1.65 Ghz), 1 CPU partition with SMT enabled Virtual I/O server

Test	Threaded=1	Threaded=0
TCP, Simplex streaming	72% CPU at 940 Mbits/sec	63% CPU at 940 Mbits/sec
TCP, Duplex streaming	87% CPU at 1420 Mbits/sec	80% CPU at 1420 Mbits/sec

The shared I/O server commands allow it to be determined if a Shared Ethernet device is threaded or non-threaded. An example is shown at the end of this article. If the threaded mode is enabled, the" Thread queue overflow packets:" statistic can be used as a indicator to tell if the packets are being dropped on the Shared Ethernet threads. These threads can queue up to 8192 input packets before the queue is overflowed and input packets are discarded. If this is occurring, the threads are not getting to run frequently enough, indicating a CPU overloaded condition. A small number of these might indicate normal behavior in a bursty network while a large number of these overflows would indicate the need for more CPU resources.

The third option is to use micro-partitioning to create two I/O Server partitions, one for the Virtual SCSI server and one for the Virtual Ethernet/ Shared Ethernet (LAN). An example might be two tenths of a CPU dedicated to Virtual SCSI and eight tenths of a CPU dedicated to Shared Ethernet. With this configuration, the hypervisor would be controlling the CPU resource and would ensure about 20% of the cycles goes to Virtual SCSI and 80% to the Shared Ethernet server. Because the two I/O servers run in different partitions, there will be minimal impact of one steeling cycles from the other. The hypervisor will ensure each I/O server partition gets its allocated quota.

Even with this configuration, under sizing the CPU's per the number of adapters in either server could still give low throughput. Proper sizing of the CPU resource for the workload is still required. With the disk and LAN servers in separate partitions, it would be easier to trouble shoot performance issues.

Here are the commands to enable or disable threading on Shared Ethernet Adapter (SEA) referred to earlier.

To enable/disable threading on the SEA adapter. Set "thread" attribute to either "0" for disabled or "1" for enabled.

chdev -dev entX -attr thread=0/1

There are two ways to check the state of threading on the SEA adapter.

The direct method

$ lsdev -dev ent5 -attr thread
value
 
0

The indirect method

$ entstat -all ent5 
ETHERNET STATISTICS (ent5) :
Device Type: Shared Ethernet Adapter
Hardware Address: 00:02:55:53:bc:d1
 
Elapsed Time: 0 days 0 hours 0 minutes 0 seconds
 
Transmit Statistics:                          Receive Statistics:
--------------------                          -------------------
Packets: 11180525                             Packets: 11180525
Bytes: 1893260976                             Bytes: 1893260976
Interrupts: 0                                 Interrupts: 1653132
Transmit Errors: 0                            Receive Errors: 0
Packets Dropped: 0                            Packets Dropped: 0
                                              Bad Packets: 0
Max Packets on S/W Transmit Queue: 122
S/W Transmit Queue Overflow: 0
Current S/W+H/W Transmit Queue Length: 0
 
Broadcast Packets: 2                          Broadcast Packets: 2
Multicast Packets: 3452                       Multicast Packets: 0
No Carrier Sense: 0                           CRC Errors: 0
DMA Underrun: 0                               DMA Overrun: 0
Lost CTS Errors: 0                            Alignment Errors: 0
Max Collision Errors: 0                       No Resource Errors: 0
Late Collision Errors: 0                      Receive Collision Errors: 0
Deferred: 1706                                Packet Too Short Errors: 0
SQE Test: 0                                   Packet Too Long Errors: 0
Timeout Errors: 0                             Packets Discarded by Adapter: 0
Single Collision Count: 0                     Receiver Start Count: 0
Multiple Collision Count: 0
Current HW Transmit Queue Length: 0
 
General Statistics:
-------------------
No mbuf Errors: 0
Adapter Reset Count: 0
Driver Flags: Up Broadcast Running
        Simplex 64BitSupport
 
--------------------------------------------------------------
Statistics for adapters in the Shared Ethernet Adapter ent5
--------------------------------------------------------------
Number of adapters: 2
SEA Flags: 00000000
    <>	<== This field will read  if thread is enabled.
VLAN Ids :
    ent4: 0 1
Real Side Statistics:
    Packets received: 2079245
    Packets bridged: 2079245
    Packets consumed: 0
    Packets received: 0
    Packets transmitted: 9101280
    Packets dropped: 0
Virtual Side Statistics:
    Packets received: 9101280
    Packets bridged: 9101280
    Packets consumed: 0
    Packets received: 0
    Packets received: 2079245
    Packets dropped: 0
Other Statistics:
    Output packets generated: 0
    Output packets dropped: 0
    Device output failures: 0
    Memory allocation failures: 0
    ICMP error packets sent: 0
    Non IP packets larger than MTU: 0
    Thread queue overflow packets: 0

HP-UX find WWN for HBAs

2011-06-22T15:13:00.001-07:00

First, list all the HBAs, in the output below the HBA device name is /dev/td0 and /dev/td1

my-hp-system# ioscan -fnkC fc

Class I H/W Path Driver S/W State H/W Type Description

=================================================================

fc 0 0/4/0/0 td CLAIMED INTERFACE HP Tachyon TL/TS Fibre Channel Mass Storage Adapter

/dev/td0

fc 1 0/7/0/0 td CLAIMED INTERFACE HP Tachyon TL/TS Fibre Channel Mass Storage Adapter

/dev/td1

Now, use the fcmsutil to find the WWN and other information related to each of these HBAs:

my-hp-system# fcmsutil /dev/td0

List top ‘paging space’ users using svmon command

2011-06-22T15:09:00.001-07:00

Here is a easy way to find the top paging space users using a svmon command:

my-system> svmon -P -O sortseg=pgsp
Unit: page
-------------------------------------------------------------------------------
     Pid Command          Inuse      Pin     Pgsp Virtual
2289864 sshd             18908     7988        0    18414
2265260 ksh              18499     7988        0    18427
1765570 svmon            17398     8032        0    17337

Network throughput test between 2 AIX servers

2011-06-22T15:06:00.001-07:00

The easiest way to test throughput between 2 AIX servers is to do a FTP test, generating data transfer with ‘dd’ command. This will provide the throughput/speed for the specified amount of data transfer:

#src-system> ftp dst-system
…
…
ftp> put "|dd if=/dev/zero bs=32k count=10000" /dev/null
200 PORT command successful.
150 Opening data connection for /dev/null.
10000+0 records in
10000+0 records out
226 Transfer complete.
327680000 bytes sent in 1.406 seconds (2.277e+05 Kbytes/s)
local: |dd if=/dev/zero bs=32k count=10000 remote: /dev/null
ftp>bye

This is the same test IBM recommends in the redbook and also during a support call

AIX file system group

2011-02-22T13:58:00.001-08:00

Group a bunch of file systems together using mount group option:
   Add an Enhanced Journaled File System
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
                                                        [Entry Fields]
Volume group name                                   datavg
SIZE of file system
          Unit Size                                   Megabytes
*         Number of units                            []
* MOUNT POINT                                        []
Mount AUTOMATICALLY at system restart?              no
PERMISSIONS                                         read/write
Mount OPTIONS                                      []
Block Size (bytes)                                  4096
Logical Volume for Log
Inline Log size (MBytes)                           []
Extended Attribute Format
ENABLE Quota Management?                            no
Enable EFS?                                         no
Allow internal snapshots?                           no
Mount GROUP                                        [asm]

FS commands to use with the mount group:

List filesystem:
[root@myserver][/]> lsfs -u asm
Name            Nodename   Mount Pt               VFS   Size    Options    Auto Accounting
/dev/asmhomelv --         /home/asm              jfs2 4194304 rw         yes no
/dev/asrouterlv --         /home/asm/asrouter     jfs2 4194304 rw         yes no
/dev/asmsavelv --         /home/asm/saveamgr     jfs2 10485760 rw         yes no
/dev/asmlv      --         /var/asm/amgrs         jfs2 4194304 rw         yes no
/dev/asmloglv   --         /var/asm/log           jfs2 10485760 rw         yes no

Mount the file system group:
[root@myserver][/]> mount –t asm

Unmount the file system group:
[root@myserver][/]>umount –t asm

Websphere MQ

2011-01-24T12:44:00.001-08:00

Create File Systems:

/usr/mqm -> MQ installation base

/var/mqm -> Queue Manager Data (log, qmgrs)

/home/mqm -> MQM user base (scripts, admin files etc)

/home/mqm/mqrouter - > MQ Router application files (scripts, config etc)

/home/mqm/saveqmgr -> Queue Manager backup location

Optional (for large installations in place of /var/mqm/):

/var/mqm/log –> Queue manager log

/var/mqm/qmgrs -> Queue manager data

Install – MQ Filesets:

mqm.base.runtime 7.0.1.3 WebSphere MQ Runtime for

mqm.base.samples 7.0.1.3 WebSphere MQ Samples

mqm.base.sdk 7.0.1.3 WebSphere MQ Base Kit for

mqm.client.rte 7.0.1.3 WebSphere MQ Client for AIX

mqm.java.rte 7.0.1.3 WebSphere MQ Java Client, JMS

mqm.jre.rte 7.0.1.3 WebSphere MQ Java Runtime

mqm.keyman.rte 7.0.1.3 WebSphere MQ Support for GSKit

mqm.msg.en_US 7.0.1.3 WebSphere MQ Messages - U.S.

mqm.server.rte 7.0.1.3 WebSphere MQ Server

mqm.txclient.rte 7.0.1.3 WebSphere MQ Extended

mqm.man.en_US.data 7.0.1.3 WebSphere MQ Man Pages - U.S.

Collect information from current server (for migrations):

On the current server, save the Queue Manager information using the saveqmgr MQ utility

#saveqmgr –m <Queue Manager Name> -s –f <File Name to save>

#saveqmgr –m <Queue Manager Name> -z -f <File Name to save>

This should create 2 files – one for the queue manager definitions and one for queue manager authorization definitions.

This utility is available from IBM WebSphere site: https://www-304.ibm.com/support/docview.wss?uid=swg24000673

Do this for all the desired Queue Managers.

Importing saved queue managers on the new server:

Create the desired empty queue mangaers on the new server:

#crtmqm – c "QM for ….env" –ll –ld /var/mqm/primary/log –md /var/mqm/primary/qmgrs –lp 3 –ls 2 <Queue Manager Name>

Start the new Queue Manager

#strmqm <Queue Manager Name>

Create the new Queue Manager definitions from the previously saved file (using saveqmgr)

#cat <QM definition file> | runmqsc <QM name>

Apply the authorization for the objects

Make the authorization file executable and execute it from the command line.

#./Authorization File

ASCII codes for backspace settings

2010-09-01T13:58:00.000-07:00

ASCII codes for backspace settings :

ASCII BS == 0x08 == ^H ASCII DEL == 0x7f == 0177 == ^?

Check runlevel on AIX

2010-08-31T13:54:00.000-07:00

Here is a handy command to see the current run level on AIX:

# who -r

. run-level 2 Aug 10 16:28 2 0 S

Retrieve SSL certificate expiration date

2010-08-30T15:16:00.000-07:00

There are several ways to extract the expiration date from the certificate file. Here is one of the easiest way if you have the file locally:

# openssl x509 –noout –in < cert_file > -dates

[root@mysystem][/opt/certificates]> openssl x509 -noout -in private_key -dates

notBefore=Jul 14 16:23:57 2010 GMT

notAfter=Jul 14 16:23:57 2012 GMT

Network problem determination: AIX tools for a systems administrator

2010-08-26T08:39:00.000-07:00

Network problem determination: AIX tools for a systems administrator

Tcpdump Recipes | danielmiessler.com

2010-08-25T15:17:00.000-07:00

Nice reference for tcpdump!

Tcpdump Recipes | danielmiessler.com

Linux Commands

2010-08-24T14:16:00.001-07:00

Few commands learned on SuSE Linux

List version of SuSE Linux:

# cat /etc/SuSE-release

Restart network:

# /sbin/rcnetwork restart

Network config files under : /etc/sysconfig/network/ directory (ifcfg-<interface name> files)

Routes in /etc/sysconfig/network/routes file

Status of the Network: ifstatus <network interface name>

Bring down netowork – ifdown <network interface name>

Bring up network – ifup <network interface name>

YaST – configuration tool for SuSE – pretty much all the system configuration can be done from this tool

Generic LVM commands in Linux:

List the physical disks installed:

# fdisk –l

Create Physical Volume (initialize physical disk for LVM)

# pvcreate /dev/sdc [or any free device name]

Create Volume group

# vgcreate myvg /dev/sdc

Create Logical Volume:

# lvcreate –L 3G –n mylv myvg

Display Commands

# pvdisplay

# vgdisplay

# lvdisplay

Create ext3 filesystem:

# mkfs.ext3 mylv

[

This filesystem will be automatically checked every 31 mounts or

180 days, whichever comes first. Use tune2fs -c or -i to override.

]

Check file system:

# e2fsck –f /dev/myvg/mylv

Extend LV:

# lvextend –L2G /dev/myvg/mylv

Resize the file system that is using the LV:

# resize2fs /dev/myvg/mylv

Remove LV:

# lvremove /dev/myvg/mylv

Change LV properties:

# lvchange

To deactivate a LV:

# lvchange -an /dev/myvg/mylv

Display all the LVs in a Volume Group (more verbose information):

# vgdisplay -v myvg

Rescan for new disks:
echo "- - -" > /sys/class/scsi_host/host0/scan

OSSEC: Invalid integrity message in t...

2010-05-27T15:13:00.001-07:00

OSSEC: Invalid integrity message in the database

To clear this message, clear the syscheck database

#/var/ossec/bin/ossec-control stop
#/var/ossec/bin/syscheck_update -a
#/var/ossec/bin/ossec-control start

Tweet up!

2010-05-27T01:43:00.000-07:00

Created a new Twitter account to publish tweets about the notes published on this site.

Code to check SSL Client Certificate ...

2010-05-25T01:06:00.001-07:00

Code to check SSL Client Certificate Expiration remotely

Language: C# (C Sharp) using MS Visual Studio Express 2010

Reference: System.Net.ServicePointManager, another sample code from stackOverflow

Code:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Net;

using System.Diagnostics;

namespace CertCheck

{

class Program

{

static void Main(string[] args)

{

//Get URL from command line to check

if (args.Length==0)

{

Console.WriteLine("Usage: CertCheck <https://url> [-v]");

Console.WriteLine("Enter an url with https prefix");

Console.WriteLine("Add -v for verbose output. By default, this will print just the number of days on the console");

return;

}

string https_url = args[0];

bool bVerbose=false;

if (args.Length > 1)

if (args[1] == "-v")

bVerbose = true;

HttpWebRequest http_req = null;

//Define the Certificate Verification Callback method

ServicePointManager.ServerCertificateValidationCallback = (state,cert,certChain,sslerr)=>

{

DateTime certExpirationDate= DateTime.Parse(cert.GetExpirationDateString());

if (bVerbose)

{

Console.WriteLine("Certificate Expires in {0} days on {1}", certExpirationDate.Subtract(DateTime.Now).Days,certExpirationDate.ToShortDateString());

Console.WriteLine("Certificate Serial Number: {0}",cert.GetSerialNumberString());

Console.WriteLine("Certificate Issued to: {0}",cert.Subject);

}

else

Console.WriteLine(certExpirationDate.Subtract(DateTime.Now).Days);

return true;

};

//Connect to the URL to validate the certificate

try

{

http_req=(HttpWebRequest)HttpWebRequest.Create(https_url);

HttpWebResponse http_resp = (HttpWebResponse)http_req.GetResponse();

http_resp.Close();

}

catch (Exception http_excep)

{

Debug.WriteLine("Error Checking site {0} : {1}",https_url,http_excep.ToString());

}

Please feel free to modify the code to fit your needs.