This article describes steps on how to generate a RMM Host Show Report, that shows Resource and Data consistency between the Source and Destination when using RMM for Migration
For this example, it is assumed that user has basic knowledge of how RMM functions and how to use RMM for their Migration and/or Disaster Recovery needs.
Use case:
We frequently encounter customers who wish to verify, either for their own confirmation, or for their end customers, or compliance purposes, etc., whether RMM was successful in:
a) Preserving data consistency, such as having a comparable number of volumes, disks, and utilized data sizes, between the ORIGIN and TARGET VMs during the migration.
b) Maintaining a similar hardware configuration, including similar amounts of memory, CPU, and network interfaces, when comparing the ORIGIN and TARGET VMs.
Background:
When migrating a virtual machine (VM) to the cloud, RMM has inbuilt capability to ensure data consistency on the TARGET VM and maintains uniformity in VM configurations, in terms of Memory, CPU, and NICs, between the ORIGIN and TARGET VMs.
Data consistency is achieved by the RMM SYNC process, which involves the capture of a point-in-time VSS Snapshot (for Windows-based systems) and LVM Snapshot (for Linux-based systems).
The use of VSS Snapshot or LVM Snapshots plays a critical role in preserving data integrity throughout the migration process. These mechanisms capture a snapshot of the data, ensuring that the data transferred to the TARGET VM remains coherent and consistent. This approach effectively minimizes the risk of data corruption or discrepancies, ensuring a smooth and dependable migration to the cloud.
It important to note that at the end of a successful SYNC, RMM ensures the data on the TARGET system, will match with that of ORIGIN system, as of the time of initiating the point in time VSS or LVM snapshot (as the case may be) on the ORIGIN system.
Assumption:
In general, the following assumptions are valid:
a) ORIGIN OS and File System type is supported per RMM Pre-Reqs for the relevant RMM version used.
b) NO volume/file/folder level exclusion is used during Migration. It is worthy to note RMM will automatically EXCLUDE any File System(s) it does NOT support (per the Pre-Reqs of RMM being used)
c) It is acknowledged and well understood that minor, nearly negligible data size mismatches can occasionally arise during VM migration processes, and this occurrence is not considered unusual.
These variations can be attributed to a range of factors, including the very important fact that ORIGIN server is ONLINE and undergoing I/O's, differences in data measurement, the presence of temporary or system files that may not require transfer, the existence of sparse files, and various technical considerations. Additionally, distinctions in file systems, compression techniques, or the handling of specific data types can lead to differences in reported data sizes.
While achieving a perfect one-to-one data size match is an ideal scenario, encountering minor discrepancies is a common aspect of the migration process. Therefore, while it may not be the primary expectation, it is a possibility that should be factored into the planning of VM migrations.
In summary, It is paramount however to prioritize data integrity, address larger-scale data discrepancies or mismatch in configurations (outside of known assumptions), and ensure the successful transfer rather, than fixating solely on achieving exact size matches.
Before you Begin:
Ensure you have 'root' user access to RMM CLI over ssh. ALL commands on the RMM CLI are to be executed as a 'root' user.
Applicable To:
~ RMM release version 7.4.x.x
~ Both Windows & Linux ORIGIN OS
Preparation/Pre-Req:
OS and Volume Type must be supported for migration by RMM and all other Pre-Reqs must be met.
Steps:
Please find attached a script named 'hostShowReport.py,' which is designed to display detailed information about RMM's ORIGIN system object and TARGET system object.
This report provides a comprehensive overview of each ORIGIN/TARGET object, including the number of disks, volumes, and used space.
(Note: I have changed the file extension to .pyd to ensure successful attachment transmission. After downloading, please rename it with a .py extension.)
Here are the steps to utilize this script:
1) Download or copy this script to the RMM server, placing it in a suitable location, such as /root/rackware/scripts.
2) Rename the file extension to .py.
3) Set the script's permissions using the command: chmod 755 hostShowReport.py
4) For usage and additional options, please run the following command:
./hostShowReport.py --help
usage: hostShowReport.py [-h] [-f FILE] [-hf HOSTFILE] [--host HOST]
optional arguments:
-h, --help show this help message and exit
-f FILE, --file FILE Name of report to generate
-hf HOSTFILE, --hostFile HOSTFILE
Specify the path to a file containing a comma separated list of hosts to generate this report for
--host HOST Comma separated list of host friendlynames to generate the report for
Here's an example of how to generate a report - this generates a report at location on the RMM at /root/rackware/results/dk_test-2.csv, containing information and details about the ORIGIN and TARGET for comparison purposes.
./hostShowReport.py -f /root/rackware/results/dk_test-2.csv
Please take a moment to download/review the sample report attached for reference.
Post Changes:
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Important Note(s):
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