What is “Tier 0” in Storage Environments?
Tier "0" is not new in storage market but for implementation purposes it has been difficult to accommodate because it requires best performance and lowest latency. Enterprise Flash disks (Solid State Disks) capable to meet this requirement. It is possible to get more performance for company most critical applications. The performance can be gained through using Flash drives supported in VMAX and DMX-4 systems. Read More →
Lets understand EMC Open Replicator product:- Open Replicator enables remote point-in-time copies with full or incremental copy capabilities to be used for high-speed data mobility, remote vaulting, migration, and distribution between EMC Symmetrix DMX and other qualified storage arrays. OR leverages the high-end Symmetrix storage architecture and offers unmatched deployment flexibility and massive scalability.
EMC Open Replicator is tightly integrated with EMC TimeFinder and SRDF families of local and remote solutions. Open Replicator Functionality:
- Protect lower-tier applications at remote locations.
- Pushing or Pulling data from Symmetrix DMX arrays to other qualified storage arrays in SAN/WAN environments.
- Create remote point-in-time copies of local production volumes for many purposes from data vaulting to remote testing and development.
- Ensure immediate data availability to host applications via Symmetrix DMX consistency technologies.
When to use EMC Open Replicator for migration:
1) SYMAPI cannot validate third party or non-visible storage systems.
2) To protect against potential data loss due to a SAN failure or other connectivity issue during a hot pull operation, use the donor update option. When enabled, this feature causes all writes to the control device from the host to be immediately copied to the remote device as well. Because the data is fully copied to both the remote device and the control devices, if a failure occurs, the session can safely be terminated and created again to fully recover from any mid-copy failure.
3) Open Replicator uses FA resources. If you are using this utility in a production environment, verify with the SA that FA bandwidth assessments have been considered and that appropriate throttling parameters (pace or ceiling).
4) When using BCVs, the BCVs must be “visible” to the remote storage array. Thus, they must be mapped to an FA and the FA must be zoned to the destination storage. We highly recommend that BCVs not be mapped to the same FA as the control standard devices to avoid a negative impact on host I/O performance.
5) If a configuration uses thin device as destination in a pull or push copy operation, full volume allocation of the thin device will be made because Open Replicator creates a full volume copy.
6) When performing an Open Replicator migration, always use the –v qualifier on the create command. This insures that, should the session fail, there will be useful information returned as to what volume caused the error. This allows you to more quickly recognize zoning or masking issues.
7) Issuing create commands prior to Open Replicator migration activities allows confirmation that there will be no zoning or masking issues discovered during the migration window. This technique will only be successful if no changes have been made to the Symmetrix environment between issuance of the create and copy commands.
8) It is better and easier to use an Open Replicator management host for preparing, executing, and monitoring migration sessions than using one of the systems with volumes involved in the activity.
9) For Veritas file systems, PowerPath devices, and Oracle databases, when you activate the copy session devices must be frozen just before the activate is performed, and thawed as soon as the activate completes. Use the following options to with the symrcopy activate command, when applicable:
-vxfs MountPoint
-ppath srcdevs
PowerPath device
-rdb dbtype DbType -db DbName
10) The device specified in the command line must match the device in the device file or the activate will fail.
PowerPath Migrator Enabler is a host-base migration tools from EMC that allows you to migrate data between storage systems with little or no interruption to data access. This tool can be use in conjunction with other underlying technology such as EMC Invista, Open Replicator. PPME use the PowerPath filter dirvers to provide non-disruptive or minimally disruptive migrations. Only specific host plateforms are supported by PPME. Please check EMC support matrix for supported host systems. One of the PPME features that supports pseduo-to-pseduo, native-to-native and native-to-pseudo device migration.
Consider the following when designing and configuring PPME:
Ø Remote devices do not have to be the same RAID type or meta-configuration.
Ø Target devices must be the same size or large than the source control device.
Ø Target directors act as initiators in the SAN.
Ø Contrary to the recommendations for Open Replicator, the source device remains online during the “hot pull.”
Ø The two storage systems involved in the migration must be connected directly or through a switch, and they must be able to communicate.
Ø Every port on the target array that allows access to the target device must also have access to the source device through at least one port on the source array. This can be counter to some established zoning policies.
Ø Since PPME with Open Replicator uses FA resources, determine whether this utility will be used in a production environment. In addition, consider FA bandwidth assessments so that appropriate throttling parameters (that is, pace or ceiling).
Ø The powermig throttle parameter sets the pace of an individual migration by using the pace parameter of Open Replicator:
Ø Faster (lower throttle) makes the migration faster, but may impact application I/O performance.
Ø Slower (higher throttle) makes the migration slower.
Ø The default is five (midpoint).
Ø When setting a ceiling to limit for Open Replicator throughput for a director/port:
Ø The ceiling value is set as a percentage of a director/port’s total capacity.
Ø The ceiling can be set for a given director, port, director and port, or all director and ports in the Symmetrix array.
Ø To set ceiling values, you must use symrcopy set ceiling directly (powermig does not provide a way to do this)
Ø Once the hot pull has completed, remove or re-use the source device.
Ø Do not forget to “clean up” the zoning once you have completed migration activities.
Hope this will be useful in migration planning or selecting migration tools. I will try to explain in deatil in coming post such as PPME with Open Replicator, Solution Enabler etc..
About Me
- Diwakar
- Sr. Solutions Architect; Expertise: - Cloud Design & Architect - Data Center Consolidation - DC/Storage Virtualization - Technology Refresh - Data Migration - SAN Refresh - Data Center Architecture More info:- diwakar@emcstorageinfo.com
Blog Disclaimer: “The opinions expressed here are my personal opinions. Content published here is not read or approved in advance by EMC and does not necessarily reflect the views and opinions of EMC.”
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