User`s manual

Sans Digital – MN4L+ Admin Guide
60
Server Fail-over & Mirror
(Additional License may required)
Server Fail-over and Mirror (SFM) is used to bind two MN4L+ NAS units as one over LAN, so as to write data to both systems simultaneously.
In addition, this feature also provides NAS/service fail-over so that network clients can be serviced by the secondary NAS in the event that
primary NAS fails. The clients accessing the primary NAS, in most cases, will not notice the fail-over process when the secondary MN4L+
takes over.
Each MN4L+ system has two groups of network port(s). One group is dedicated for client serving (Data ports) and the other group is
dedicated for data copying and communicating (SFM ports) with each other. Both groups of network ports may be bonded for higher
throughput as well as fail-over within NIC ports.
CAUTION: SFM is intended to be used for NAS units within the same local LAN, and not for over the WAN/VPN/Internet.
Before configuring SFM:
• Both systems should have at least one NIC port dedicated for SFM use. Connection between two systems may be via. cross over
cable, or, on a switch. When using the switch, it is recommended that the switch for SFM ports be separate from Data ports.
Note: SFM port may be configured simply by clicking on the available port and selecting SFM. TCP/IP information is not needed for
SFM port.
• Both systems must have same number of PV’s and LV’s as well as same capacity for PV’s and LV’s. Name the PV’s
and LV’s the same for both systems.
• Both systems should be connected to the same subnet.
• If ADS/PDC and/or NIS synchronization is planned, synchronize ADS/PDC and/or NIS before starting SFM configuration for the
primary server. If ADS/PDC and/or NIS synchronization need to be disabled, disable SFM first.
• Plan 3 IP addresses:
1. Data IP address for primary NAS. For example, 10.1.1.100
2. Data IP address for secondary NAS. For example, 10.1.1.101
3. IP address for Virtual Service port. Virtual Service port is used for clients to connect to MN4L+ in SFM mode. For
example, 10.1.1.200
4. For this manual, following IP addresses will be used for example:
 Primary NAS IP address: 10.1.1.100
 Secondary NAS IP address: 10.1.1.101
 Service(virtual) port IP address: 10.1.1.200
To Configure SFM:
1. Power up primary NAS. Secondary NAS must be turned off.
2. Configure the TCPI/IP for Data port and SFM port in Network Setting / TCP/IP configuration. IP address for primary server’s Data
port would be (10.1.1.100). SFM port is auto-assigned by MN4L+, simply click on the available NIC port, SFM radio button and
Apply
3. Go to SFM page found in Backup, Mirror and Restore section, and select Primary radio button. Input Service(virtual) IP
address, (10.1.1.200) and Secondary NAS Data port IP address, (10.1.1.101)
4. Reboot the primary server. Configuring primary NAS is done
5. Power up secondary NAS. Primary NAS should be on at this time
6. Configure the TCP/IP for Data port and SFM port in Network Setting / TCP/IP configuration. IP address for secondary server’s
Data port would be (10.1.1.101). SFM port is auto-assigned by MN4L+, simply click on the available NIC port, SFM radio button
and Apply
7. Go to SFM page found in Backup, Mirror and Restore section, and select Secondary radio button. Input Service IP address,
(10.1.1.200) and Primary NAS data port IP address, (10.1.1.100)
8. Reboot the secondary NAS.
9. Both systems’ SFM page will indicate that sync. is configured.
10. Clients need to map to the network storage available from 10.1.1.200 (virtual service port ip)
11. If the primary server should fail due to:
a. Disconnected NIC port
b. Power outage
c. RAID volume corruption
d. OS kernel panic
12. Secondary server will take over the service and all data on the primary server will be available.
To Re-Deploy failed Primary NAS:
1. Fix the problem that disabled the primary NAS. Note: The re-deployment of the primary NAS is so that it can become the
secondary NAS. Former secondary NAS is now the primary NAS
a. MN4L+ server to be re-deployed must meet the requirement detailed under Before configuring SFM.
b. Configure TCP/IP for the Data port. In line with above example, Data port IP address would be (10.1.1.100)
c. Follow steps above to configure the NAS to synchronize with primary NAS (formerly secondary NAS)
d. Boot the former primary NAS, it will sync and take position of secondary NAS