NetApp vFiler DR with Data ONTAP Simulator Part 7: Synchronous vFiler DR

Feb 12, 2016 4 min read netapp

This article is part of a series.

Note: You can skip this instructions if you only need a asynchronous mirror like described in part 6 and already configured vFiler DR.

In part 6 of this series vFiler DR was created with a asynchronous SnapMirror. This means it takes some time before the data of the vFiler is mirrored to the second simulator. To make sure data is written to the vFiler and its mirror simultaneously you have to create a synchronous SnapMirror. This works only if the volumes of the vFiler have a size of at least 10 GB (as created in part 4). In addition you have to make sure DNS name resolution is working (each simulator has to be able to resolve the other one). If you didn’t configure the DNS settings during initial setup of the simulators (also not configured in part 1) you can do so via OnCommand System Manager (Configuration => Network => DNS). If no DNS server is available you can also add the IPs to the file /etc/hosts on both simulators.

netapp01> rdfile /etc/hosts
127.0.0.1 localhost localhost-stack
127.0.10.1 localhost-10 localhost-bsd
127.0.20.1 localhost-20 localhost-sk
192.168.2.66    netapp01 netapp01-e0a
# 0.0.0.0       netapp01-e0b
# 0.0.0.0       netapp01-e0c
# 0.0.0.0       netapp01-e0d

netapp01> wrfile /etc/hosts
127.0.0.1 localhost localhost-stack
127.0.10.1 localhost-10 localhost-bsd
127.0.20.1 localhost-20 localhost-sk
192.168.2.66    netapp01 netapp01-e0a
# 0.0.0.0       netapp01-e0b
# 0.0.0.0       netapp01-e0c
# 0.0.0.0       netapp01-e0d
192.168.2.67    netapp02
read: error reading standard input: Interrupted system call

netapp01> rdfile /etc/hosts
127.0.0.1 localhost localhost-stack
127.0.10.1 localhost-10 localhost-bsd
127.0.20.1 localhost-20 localhost-sk
192.168.2.66    netapp01 netapp01-e0a
# 0.0.0.0       netapp01-e0b
# 0.0.0.0       netapp01-e0c
# 0.0.0.0       netapp01-e0d
192.168.2.67    netapp02

rdfile /etc/hosts is used to get the content of /etc/hosts. Unfortuantely you can not edit the file and have to overwrite it ínstead. Copy the output of rdfile and start to overwrite the file with wrfile /etc/hosts. Paste the content of the clipboard and add a line consisting of the IP of the other simulator and its hostname. After this exit editing the file with Ctrl+C. Now you can check your changes with rdfile /etc/hosts again. See a short video which demonstrates the steps on the second simulator (netapp02).

You can check the configuration with a ping on each of the both simulators:

netapp01> ping netapp02
netapp02 is alive

netapp02> ping netapp01
netapp01 is alive

vFiler DR is almost configured the same way as described in part 6. The only difference is the option -s you have to add to the command.

netapp02> vfiler dr configure -s vfiler01@192.168.2.66
One can optionally provide an alternate ip
 path for sync snapmirroring
Alternate IP address/Hostname for remote filer 192.168.2.66 []:
Alternate IP address/Hostname for local filer netapp02 []:
192.168.2.66's Administrative login: root
192.168.2.66's Administrative password:
Configuring SnapMirror to mirror vfiler vfiler01's storage units from remote filer 192.168.2.66.
Upon Activation, configure vfiler IP address 192.168.2.68? [y]:
Interface to assign this address to {e0a, e0b, e0c, e0d}: e0a
Netmask to use: [255.255.255.0]:
Starting snapmirror initialize commands. It
could take a very long time when the source or
destination filers are involved in many
simultaneous transfers. The console will not be
available until all initialize commands are
started successfully. Please use the
"snapmirror status" command on the source
filer to monitor the progress.

Volume 'vol_vfiler01' is now restricted.
Upon activation, do you want the DR vfiler to use a different
set of DNS servers from the production vfiler? [n]:
SnapMirror transfer initiated for vfiler storage units.

When you check the state with snapmirror status ist looks like a asynchronous SnapMirror at first. But after the first initial mirroring the state changes to “In-sync”.

netapp02> snapmirror status
Snapmirror is on.
Source                                  Destination            State          Lag        Status
192.168.2.66_vfiler01_con:vol_vfiler01  netapp02:vol_vfiler01  Snapmirrored   00:00:30   Idle

netapp02> snapmirror status
Snapmirror is on.
Source                                  Destination            State          Lag        Status
192.168.2.66_vfiler01_con:vol_vfiler01  netapp02:vol_vfiler01  Snapmirrored   00:00:00   In-sync

If the state does not change to “In-sync” entries in the Syslog might help to troubleshoot. You can find them in OnCommand System Manager (Diagnostics => Logs => Syslog). For example with incorrect DNS configuration I got the errors “SnapMirror is unable to setup a multipath connection to vol_vfiler01, resorting to the standard single TCP connection.” and “SnapMirror: destination transfer from 192.168.2.66_vfiler01_con:vol_vfiler01 to vol_vfiler01 : Error in snapmirror sync mode negotiation.”.

All articles of the series
Part 1: Download of the files needed
Part 2: Configuration of the first simulator
Part 3: Configuration of the second simulator
Part 4: Create an aggregate and volume
Part 5: DNS Configuration
Part 6: Create vFiler and configure vFiler DR
Part 7: Synchronous vFiler DR
Part 8: Create shares on vFiler
Part 9: Planned Failover
Part 10: Disaster Failover