Level: Intermediate Manohar Rao Bodke (manoharrao@in.ibm.com), Test Engineer, IBM India Private Ltd.
13 May 2008 HACMP/XD uses PPRC mirroring technology to provide disaster
recovery for critical applications' data. To achieve high availability for
distributed applications over extended distances, administrators need to configure
PPRC in an HACMP/XD environment. This involves collecting configuration data from
the storage as well as from the cluster nodes; at times this can be tedious. This
article shows you how, using pprc4hacmp, configuration data is generated automatically for
HACMP/XD-PPRC.
Introduction
The pprc4hcmp script is a tool that automatically generates configuration data for
HACMP/XD-PPRC with minimal user input and helps in complex PPRC
configuration under the HACMP/XD environment. Users should have minimal High
Availability Cluster Multi Processing (HACMP) and IBM® AIX®
knowledge to use this tool. A typical PPRC configuration requires identifying the
PVIDs,VGnames, and Hostnames, and more. The main intention of the tool discussed
in this article is that it generates PPRC-related configuration data that is required to configure HACMP PPRC.
Users just need to collect data from this tool and use it in configuring PPRC using SMIT. Those who have base HACMP and AIX knowledge can benefit from this tool by a great deal by leveraging from its centralized automated configuration data discovery.
What is HACMP/XD?
HACMP Extended Distance (HACMP/XD) is a software solution for disaster
recovery, and is an extension to the base HACMP software that enables a
cluster to operate
over extended distance at two sites. In case of failure at the production
site, HACMP/XD moves the application to the backup site, which is at a remote
location. When the application is restarted on the remote site, the remote
site should contain the data that was used by the application on the primary
site, so that the applications can provide services to clients without data loss. As the sites are normally spread across different locations with larger distances, users need to use PPRC or XD technology.
HACMP uses different mirroring technologies to achieve this. They are:
- GLVM -- Geographical Logical Volume Mirroring
- HAGEO
- PPRC by IBM System Storage™ DS8000™/DS6000™/ESS800™
- SVC-PPRC
Customers often choose to use PPRC, as it is faster compared to network XD
technologies. This article deals with HACMP/XD using PPRC with IBM System
Storage.
What is PPRC?
Peer-to-peer remote copy (PPRC) is a protocol to mirror a disk from one storage
system to
another disk in a remote site. PPRC can be used to provide fast data recovery
after
failure of the primary site. PPRC is classified as synchronous and
asynchronous. Synchronous PPRC causes each write to the primary volume to be
performed to the secondary as well, and the I/O is only considered complete when the
update to both primary and secondary have completed. Asynchronous PPRC I/O is
considered to be completed immediately after performing the I/O on primary
volume,and performs I/O to the secondary volume asynchronously. The IBM System
Storage DS8000,
DS6000,
and ESS800 devices support PPRC.
What is DSCLI?
The DS command line interface (DSCLI) provides several commands to configure
storage, such as adding host information, assigning disks, and the like. It also provides copy
services commands used to configure PPRC.
What is ESSCLI?
The ESS command line interface (ESSCLI) is similar to DSCLI but is only applicable
to ESS800 storage units. But to work with copy services, you can use DSCLI with
both DS and ESS. If the HACMP cluster has both DS and ESS as part of the cluster, both DSCLI and ESSCLI need to be installed.
Sample PPRC setup
A typical PPRC setup is shown in Figure 1. To start PPRC, the minimal required
resources are two storage systems connected with FCP/ESCON links.
Figure 1. Sample PPRC setup
This sample PPRC setup consists of two storage units; one is located at the production
site and another is at a backup site. I have chosen two disks;
one is from the DS8000 series with a volume ID of 0620 on the production site, and
another is from the ESS800 series with a volume ID
103Fm on the backup site. They are connected with an FCP link. The volume ID of the
disk is a combination of the LSS (Logical Sub System) and the disk sequence number. In this
case, LSS is 06 and 20 is the sequence number of the disk. The PPRC path is a logical
path that is defined between the primary LSS and the secondary LSS. These logical
paths are defined over physical links between disk subsystems. Each physical link
includes a host adapter in the primary disk subsystem and a host adapter in the secondary disk subsystem.
Follow these steps to establish a PPRC relationship:
- Establish a pprcpath between LSS 06 -> 10 using the
mkpprcpath dscli command
- Establish a pprc relationship between 0620-> 103F using the
mkpprc dscli command
- Check for the pprcstate using the
lspprc dscli command. If the state is full
duplex, the two disks are in sync.
If you are establishing the PPRC relationship, use
mode=FULL
so that the remote disks will be mirrored completely
(including VGDA). If it is already established and you don't want to start
mirroring immediately, use
copymode=nocopy
. In the
article, we are dealing with the Metro mirror, so select
type=mmir
.
Example commands
The following code listing is a sample of DSCLI commands.
Listing 1. Example DSCLI
commands
#/opt/ibm/dscli/dscli -user xxxxx -passwd xxxxx -hmc1 aaa.bbb.ccc.ddd
Date/Time: December 17, 2007 1:39:11 AM CST IBM DSCLI Version: 5.2.400.426
DS:IBM.2107-xxxxxxx
(To list available PPRC Ports between two storage systems)
dscli> lsavailpprcport -l -remotewwnn 500507630EFFFDE4
IBM.2107-7516231/06:IBM.2105-22012/10
Date/Time: March 30, 2007 5:36:35 AM CDT IBM DSCLI Version: 5.2.400.426
Local Port Attached Port Type Switch ID Switch Port
===================================================
I0000 I0001 FCP NA NA
I0000 I0002 FCP NA NA
I0000 I0100 FCP NA NA
(To Establish PPRC path between LSS 06 and LSS 10 )
dscli> mkpprcpath -dev IBM.2107-7516231 -remotedev IBM.2105-22012 -remotewwnn
500507630EFFFDE4 -srclss 06 -tgtlss 10 i0000:i0100
Date/Time: April 20, 2007 6:27:42 AM CDT IBM DSCLI Version: 5.2.400.426 DS:
IBM.2107-7516231
CMUC00149I mkpprcpath: Remote Mirror and Copy path 06:06 successfully established.
(To establish PPRC metro mirror relationship between disks 0620 and 100F )
dscli>mkpprc -dev IBM.2107-7516231 -remotedev IBM.2107-13AAY4A -type mmir
-mode full 0620:100F
Date/Time: April 20, 2007 6:31:45 AM CDT IBM DSCLI Version: 5.2.400.426 DS:
IBM.2107-7516231
CMUC00153I mkpprc: Remote Mirror and Copy volume pair relationship 0620:100F
successfully created.
|
 |
Configure HACMP/XD and PPRC
Say an application is using these disk to store its data and the customer wants
to make this application highly available using HACMP. Making application highly
available is not sufficient; we should also make the disk data highly available to achieve complete high availability. This is can be achieved by using HACMP/XD with PPRC.
Let us consider the example discussed in the Sample PPRC setup section.
Figure 2. A simple two-site HACMP/XD cluster with PPRC setup
First, configure a base HACMP/XD cluster which consists of one node per site. Each site
has disks assigned from storage. In Figure 2, node1 and DS8000 are
the hostname of the server and storage located at siteA, respectively. And node2 and
ESS800 are the node name of the server and storage type that are located at siteB.
Assuming that we have already established the PPRC relationship, the only thing needed
is to integrate this to HACMP.
To integrate existing PPRC to HACMP, we have to configure the following:
- Copy services configuration
- DS ESS disk subsystems
- DSCLI Managed PPRC Replicated Resource
Let's start with how to collect the required data to configure the items as shown
in Figure 2. The disk 0620 is visible as hdisk10 on node1. And the disk 103F is
visible as hdisk5 on node2. The user does not know the storage-related information. He just knows the PPRC disks are hdisk10 and hdisk5 and their PVIDs.
Note that once the two disks are in PPRC, they acquire the same PVIDs. After establishing
the PPRC between the two disks, the remote disks' VGDA is replaced with the VGDA of the
local disk so that they have the same PVIDs.
Now, if you want to integrate these disks (make VGs on these disks highly available)
with HACMP, you need to collect the information like storage ID, volume ID, LSS ID,
pri-sec portID, and sec-pri PortIDs. These can be collected using DSCLI commands as
mentioned earlier. Instead of going through this process, use the pprc4hacmp script, which generates all this configuration data for you.
The assumptions here are:
- That DSCLI is installed on all nodes and is in the /opt/ibm/dscli directory.
- You are able to
rsh or ssh from the current node to the remote node.
- Two possibilities are considered: one is if PPRC is already configured (configured
here means with respect to storage, not with HACMP) and another is a new PPRC
configuration. This article deals with an existing PPRC.
You just need to pass the site names, node name (hostnames), PVIDs, and DS/ESS HMC IPS
for each storage system. The pprc4hacmp script generates
configuration data that you need to enter as part of the HACMP-PPRC configuration. It
generates configuration data in two formats:
- Colon-delimited
- SMIT snapshot
How to use pprc4hacmp
The pprc4hacmp script can be operated in two modes:
- Interactive mode
- Non-interactive mode
Interactive mode
To start in interactive mode, enter the following:
When you run the script as shown above, it prompts for several inputs that are used in
generating the required HACMPPPRC configuration. These inputs are needed because in
this mode the tool is not using any of the HACMP utilities or commands to get the configured cluster information.
Listing 2. Interactive mode example
# pprc4hacmp.sh
Enter primary Site Name......:
Site A
Enter one node from Primary Site ....:
Node1
Enter Secondary Site Name ......:
SiteB
Enter one node from secondary Site .....
Node2
Enter VG name ...:
RG1_CG1
Enter PVIDs@SiteA of all disks for the VG -RG1_CG1 separated by space...:
00c46a1d4e588ed3
Enter PVIDs@SiteB of all disks for the VG -RG1_CG1 separated by space...:
00c46a1d4e588ed3
Enter DS HMC ip at SiteA ....:
192.168.1.141
Enter username for 192.168.1.141.....:
unamexx
Enter password for 192.168.1.141.....:
passwordxx
Enter Storagetype for 192.168.1.141.....:
2107
Enter DS HMC ip at SiteB ....:
192.168.2.210
Enter username for 192.168.2.210.....:
unamexx
Enter password for 192.168.2.210.....:
passwordxx
Enter storage type for 192.168.2.210.....:
2105
validating input........
|
Non-interactive mode
To start in non-interactive mode, enter the following:
#pprc4hacmp -i [variablefile] |
The variablefile is a file that contains the required input information in a
specific manner, as shown in the listing below:
Listing 3.
Variable file template
PRISITE:sitename:nodename@site1
SECSITE:sitename:nodename@site2
PRIDSINFO:primary HMCip:username:password:storage Type
SECDSINFO:primary HMCip:username:password:storage Type
VGNAME:volumegroupname which is on pvs
PRIPVS:pvids from primary site
SECPVS:pvids from secondary site
|
Listing 4.
Example variable file
PRISITEINFO:SiteA:Node1
SECSITEINFO:SiteB:Node2
PRIPVs: 00c46a1d4e588ed3
SECPVs: 00c46a1d4e588ed3
PRIDS:192.168.1.141:unamexx:passwordxx:2107
SECDS:192.168.2.210:unamexx:passwordxx:2105
VGNAME:RG1_CG1
|
Format 1.
Non-interactive mode, colon-delimited format
# pprc4hacmp.sh -i varfile -c
validating input........
Searching for DSCLI on node Node1 .......
DSCLI found on node Node1
Searching for DSCLI on node Node2 .......
DSCLI found on node Node2
HMC 192.168.1.141 ping test ....... Success
Storage Image id managed by HMC- 192.168.1.141 ........... : IBM.2107-7516231
HMC 192.168.2.210 ping test ....... Success
Storage Image id managed by HMC- 192.168.2.210 ........... : IBM.2105-22012
Verifying PVs existence at SiteA......
Verifying PVs existence at SiteB.....
Verifying PV Vs LSSs on each Site ........
Finding LSS and VOlume PAIRs ......
Finding Pri-sec and sec-pri PortIDs for the Lsss 06 10.......
--------------- Copyservices Server Configuration data -------------------
CSSINFO:css_SiteA:DSCLI:SiteA:192.168.1.141:unamexx:passwordxx
CSSINFO:css_SiteB:DSCLI:SiteB:192.168.2.210:unamexx:passw0rdxx
----------------------------------****------------------------------------
------------------ DS ESS Subsystem Configuration data -------------------
DSESSINFO:dsess_SiteA:SiteA:192.168.1.141:unamexx:passwordxx::IBM.2107-7516231 :css_SiteA
DSESSINFO:dsess_SiteB:SiteB:192.168.2.210:unamexx:passwordxx::IBM.2105-22012 :css_SiteB
----------------------------------****------------------------------------
-------------DSCLI-Managed PPRC Replicated Resource Configuration---------
PPRC_REP_RES:PPRC_RG1_CG1:SiteA SiteB: 0620->103F:dsess_SiteA dsess_SiteB:06 10:
mmir:I0000->I00A4 I0002->I00A4:I0020->I0330 I0020->I0333:FCP:OFF:MANUAL:RG1_CG1
----------------------------------****------------------------------------
|
Output can be obtained in two formats, colon-delimited format
and SMIT-snapshot format.
Format 2.
Non-interactive mode, SMIT snapshot format
# pprc4hacmp.sh -i varfile
validating input........
Searching for DSCLI on node Node1 .......
DSCLI found on node Node1
Searching for DSCLI on node Node2 .......
DSCLI found on node Node2
HMC 192.168.1.141 ping test ....... Success
Storage Image id managed by HMC- 192.168.1.141 ........... : IBM.2107-7516231
HMC 192.168.2.210 ping test ....... Success
Storage Image id managed by HMC- 192.168.2.210 ........... : IBM.2105-22012
Verifying PVs existence at SiteA......
Verifying PVs existence at SiteB.....
Veryfying PV Vs LSSs on each Site ........
Finding LSS and VOlume PAIRs ......
Finding Pri-sec and sec-pri PortIDs for the Lsss 06 10.......
--------------- Copyservices Server Configuration data -------------------
* CSS Subsystem Name [css_SiteA]
* CSS Site Name SiteA +
* CSS IP Address [192.168.1.141]
* CSS User ID [unamexx]
* CSS Password [passwordxx]
----------------------------------****------------------------------------
--------------- Copyservices Server Configuration data -------------------
* CSS Subsystem Name [css_SiteB]
* CSS Site Name SiteB +
* CSS IP Address [192.168.2.210]
* CSS User ID [unamexx]
* CSS Password [passwordxx]
----------------------------------****------------------------------------
------------------ DS ESS Subsystem Configuration data -------------------
* ESS Subsystem Name [dsess_SiteA]
* ESS Site Name SiteA +
ESS Cluster1 IP Address [192.168.1.141]
ESS Cluster2 IP Address [ ]
* ESS User ID [unamexx]
* ESS Password [passwordxx]
* Full ESS Storage ID [IBM.2107-7516231]
* List of CS Servers [css_SiteA] +
----------------------------------****------------------------------------
------------------ DS ESS Subsystem Configuration data -------------------
* ESS Subsystem Name [dsess_SiteB]
* ESS Site Name SiteB +
ESS Cluster1 IP Address [192.168.2.210]
ESS Cluster2 IP Address [ ]
* ESS User ID [unamexx]
* ESS Password [passwordxx]
* Full ESS Storage ID [IBM.2105-22012]
* List of CS Servers [css_SiteB] +
----------------------------------****------------------------------------
-------------DSCLI-Managed PPRC Replicated Resource Configuration---------
* PPRC Resource Name [PPRC_RG1_CG1]
* HACMP Sites [SiteA SiteB] +
* PPRC Volume Pairs [ 0620->103F]
* ESS Pair [dsess_SiteA dsess_SiteB] +
* LSS Pair [06 10] +
* PPRC Type mmir +
* Pri-Sec Port Pair IDs [I0000->I00A4 I0002->I00A4]
* Sec-Pri Port Pair IDs [I0020->I0330 I0020->I0333]
* PPRC Link Type FCP +
* PPRC Critical Mode OFF +
* PPRC Recovery Action MANUAL +
* Volume Group [RG1_CG1]
----------------------------------****------------------------------------
|
|
Configuring CSS, DSESS, and PPRCs
The user uses the configuration data and smit pprc_ds to
configuration HACMP.
Listing 5. Where to use the generated configuration data
smit pprc_ds
--------------------------------------------------------------------
Copy Services Server Configuration
DS ESS Disk Subsystem Configuration
DSCLI-Managed PPRC Replicated Resource Configuration
PPRC Consistency Groups Configuration
Verify PPRC Configuration
|
From the above smit menu:
- Choose the Copy Services Server Configuration option and configure CSS
- Choose DS ESS Disk Subsystem Configuration and configure DS ESS subsystem
- Choose DSCLI-Managed PPRC Replicated Resource Configuration and configure the
PPRC-replicated resource
Summary
You only need basic knowledge of HACMP and AIX to use this utility. Using the
configuration data generated by the pprc4hacmp tool can save you time as well as reduce
or eliminate the chances of mistake in configuration. The user does not need to know
about DSCLI commands, format of output, and different fields of output. So users can use
this script to configure PPRC easily.
Download | Description | Name | Size | Download method |
|---|
| pprc4hacmp script file | pprc4hacmp.zip | 100KB | HTTP |
|---|
Resources Learn
Discuss
-
Participate in the AIX and UNIX forums:
About the author  | | | Manohar Rao has a Bachelor's degree in Electrical and Electronics Engineering from Jawaharlal Nehru Technological University and joined IBM in 2006. He is a test engineer working on HACMP/XD Disaster Recovery. His interests are test automation and implementing tools for testers that makes their jobs easier. Outside of IBM, his hobbies are chess, reading, movies, and friends. You can reach him at manoharrao@in.ibm.com. |
Rate this page
| 
