Addition of multiple file systems to a Replicated Volume Group
Access Appliance supports the addition of multiple file systems to a Replicated Volume Group (RVG). You can enable replication for many file systems in a single RVG.
Considerations while configuring Access Appliance for continuous replication:
The number of RVGs configured under continuous replication on Access appliance should be restricted to 4.
The number of file systems under one RVG should be limited to 12.
Veritas recommends that you to add one file system at a time to an RVG. Once the file system is added and the status of continuous replication becomes consistent (up-to-date), add another file system to the RVGs.
Ensure that continuous replication IPs configured on Access Appliance are properly resolved by the configured DNS server or by
/etc/hostsfile.Addition of multiple file systems to an existing Replicated Volume Group is supported only through CLISH.
If you try to add a file system to an existing RVG when the replication continuous enable operation is in progress, then the file system remains offline till the operation is complete. As a result, the application is not able to serve read-write requests. The time period for which the file system remains offline depends on the size of the file system and the amount of data present on it. Ensure that you consider this downtime before you run the replication continuous enable command.
To configure an RVG with multiple file systems
- Create an RVG. You can specify the name in the parameter.
replication> continuous enable fs_name pool_name link_name [delayed=yes|no] rvg_name create_target_fs srl_size
fs_name
Specifies the name of the file system. It should be present on the source cluster.
pool_name
Specifies the pool name. It should be present on the source as well as destination cluster.
link_name
Specifies the link name. This link is created during authentication of the source and the destination cluster,
[delayed=yes|delayed=no]
Specifies if the continuous replication should happen in delayed mode. This is an optional parameter, and the default value is 'no'.
rvg_name
Specifies the name of the RVG.
create_target_fs
The value is yes if you want to create file system on secondary cluster. Else, the value is set to no.
srl_size
Specify the SRL size for the file system.
For example: To create an RVG,
rvg_test:replication> continuous enable fs1 pool1 src_link delayed=yes rvg_test
You can specify the RVG name in the command. If the RVG name is not specified, the RVG is created with the default name. The default name of the RVG is rvg_fs_name.
- Before adding another file system, ensure that the data is synced between the primary and secondary sites and the second file system is offline.
replication> continuous status fs_name
- Add another file system to the same RVG.
replication> continuous enable fs_name pool_name link_name [delayed=yes|no] rvg_name
Note:
If you have configured any NFS shares on the file system, you must remove them before you add the file system to an existing RVG.
For example: To add a file system.
fs2to the existing RVG, rvg_test:replication> continuous enable fs2 pool1 src_link delayed=yes rvg_test
After the execution of this command, rvg_test is created with two file systems in it, fs1 and fs2.
You can add more file systems in the RVG by repeating steps 2 to 3.
You can view the mapping between the RVG and the file systems using the following command:
replication> continuous show RVG FS List ------ --------------- rvg_test fs1,fs2
The replication continuous commands such as start, stop, pause, resume, failover, and failback accept the file system name as the parameter, but the changes are applicable for the entire RVG (including all the file systems which are part of the RVG).
For example, if you have multiple file systems in an RVG and if you failover using the replication continuous failover fs1 command, then the entire RVG will fail over.
The replication continuous disable command does not delete the RVG until the file system is the last file system in the RVG.
For each file system that is added to the RVG, if the file system is configured in async mode, the Storage Replicator Log (SRL) grows by 20% of the file system size, and if the file system is configured in sync mode, it grows by 5% of the file system size. If the SRL has been grown more than 12 times(either as a result of the fs grow command or addition of file systems to the RVG), then the SRL is not grown further.
You can also set the maximum SRL size for an RVG.
replication> continuous config set_max_srl_size rvg_name size
For example, the following command sets the SRL size to maximum of 200GB for rvg_test.
replication> continuous config set_max_srl_size rvg_test 200G
You can also use the replication continuous enable command for setting the RVG size.
replication> continuous enable fs1 pool1 source delayed=yes rvg_test create_target_fs=yes 100G
Here, 100G is the SRL size for rvg_test, which is an optional parameter.
This option is useful when setting the SRL size for the first file system when an RVG does not exist.
You can also view the current SRL and maximum SRL size. Appropriate messages are shown after the completion of each command to inform the user about successful completion or reason for failure.
You can verify whether the file systems are added correctly and the appropriate SRL size is set.
replication> continuous show
RVG FS List SRL Size ============= ========= ======== rvg_test fs1,fs2,fs3 204m
You can also verify whether the maximum SRL size is set correctly.
replication> continuous config show
Link name Remote Console IP Remote Replication Time of Key Import
VIP
========= ================= =================== ===========================
clus_repl 10.221.35.102 10.221.35.104 Tue Oct 12 23:22:19 PDT 2021
Time of Authorization RVG Max SRL Size
============================ ============== =================
Tue Oct 12 23:23:32 PDT 2021 rvg_test -
rvg_test2 19g
rvg_test3 10g
rvg_test4 11g