Tuesday, July 3, 2012
Thursday, June 7, 2012
I was recently involved in an engagement to implement SRM 5 with a Dell Compellent storage solution. During the engagement we had various issues around how to implement the Dell components. Dell have produced a best practice document but some elements of the document are a little light on the ground. This blog is a collection of tested procedures that we followed to prove the solution.
Setting up the EnvironmentDuring our testing we setup the environment using the following steps:
1. Set up the LUNs and replication using Compellent Enterprise Manager client.
2. Save the restore points using Enterprise Manager client. This is a manual process that Dell talks about within their Best Practice guide and must be done after all major SRM events.
3. Set up datastores in vSphere and present them to the appropriate hosts.
4. Create a Protection Group(s) in SRM for the newly created datastores.
5. Create a Recovery Plan(s) in SRM for the newly created datastores.
6. Configure SRM debug logging in both Data Collectors to collect SRM information. (We did this step in order to capture detailed logging to provide Dell if required)
7. Confirmed that the SiteA SRA was talking to the remote data collector (hosted in SiteA) and the SiteB SRA was talking to primary data collector (hosted in SiteB), as per Compellent Best Practice. (This configuration is not 100% clear in the best practice document and we were provided conflicting information from Dell Support when we asked for verification, the document did not define Primary vs Remote Data Collectors and simply referred to Enterprise Manager in both sites.
Defining the Failover procedure
We defined the following procedure to be run during a failover type of 'Disaster Recovery':
Defining the Failback procedure
We defined the following procedure to be run during a failback type of 'Disaster Planned Migration:
1.Run the same Recovery Plan as used for the Failover procedure, selecting 'Planned Migration' as the recovery type.
TestingAfter defining the procedures we then carried out the following tests to verify the process.
Test 1 - Both Compellent Enterprise Manager data collectors running
Test 2 - Primary data collector shut down
Test 3 - Remote data collector shut down
Wednesday, June 6, 2012
A. The issue around DHCP is Microsoft-related and not VMware. The problem is that we rely on Sysprep to perform the customization and this is where the DHCP requirement comes in. As a workaround, we ran a script called SetupCommand.cmd which calls the netdom.exe command with the following syntax:
netdom.exe join %COMPUTERNAME% /Domain:vmware.com /OU:OU=vApp-VMs,DC=vmware,DC=com /Userd:???? /PasswordD:???? /Reboot
To configure this:
1. Before submitting the vApp to the catalog
2. Right click the VM and select ‘Properties’
4. Scroll down to the ‘Customization Script’ sections and enter your command:
Friday, June 1, 2012
If using a VM for the SRM server ensure the following are configured before attempting to install the SRM components:
1. RDM presented to the SRM VM, attached, initialized, but not formatted or assigned a drive letter.
2. Install Hitachi RAID-Manger/Command Control Interface to setup the HORCM service (Protected site HORCM0 & Recovery Site HORCM1).
3. Configure the horcm0.conf and horcm1.conf files on the respective SRM Servers.
4. Start HORCM service (you will need to alter the name of the run config file located in the C:\HORCM\Tools, to match the service name 0 or 1.
5. Test connection locally using C:\HORCM\Tools\pairdisplay –g GRP1 –l (for local check) and pairdisplay –g GRP1 –fcx (remote side check), alter GRP1 to match the Group defined in your HORCM.conf file.
Answer: HUR keeps all LUN pairs in the JNL group in the same status so if the pairs are split for a failover, all pairs in the JNL groups are split. The SRA cannot override this behavior. To split a single LUN it must be in a JNL group without any other LUNs.
Can SRA do split/sync for just one LUN ?
Answer: Yes, depending on the configuration of HORCM but this is possible. The HUR pairs need to be created as single LUN/JNL group.
If we have multiple LUN's in same journal does it split all LUN's at same time?
Does the SRA start a reverse sync immediately (Reverse P-VOL and S-VOL) once the secondary site is brought up?
Answer: With SRM 4, HUR / TC do horctakeover so replication is reversed and if possible resync is run in the reverse direction. This behavior was changed for SRM 5 to support the additional functions. SRM 5 will only split and reverse the replication but will not resync until the reverseReplication function is called.
Do we have to create a separate HUR journal for each LUN, for individual LUN failover/failback?
Answer: A separate JNL Group.
Friday, April 20, 2012
Trouble is it took a little while to find so for future reference and in case anyone else needs to get hold if it in a hurry the download and documentation can be found using the following communities link: