Updating MTU size after resizing to MANA enabled Azure VMs – FlashGrid Help Center

Customers who resize their VMs from non-MANA to MANA based VM series may see network and storage performance improvements by increasing MTU to 9000 bytes. This article describes steps required to update the MTU size after resizing all cluster nodes to MANA based VM series.

Note: The MTU modification requires stopping Oracle services on all database nodes. Plan a maintenance window accordingly.

Note: After increasing the MTU size, you can no longer resize the VMs back to any non-MANA based VM series.

Note: MTU=9000 is configured by default on FlashGrid systems deployed using FlashGrid Launcher version >=26.03 and MANA enabled VM series.

Updating MTU size (requires database downtime)

Note: "All nodes" refers to all database, storage, and quorum nodes.

First DB node: Make sure there are no nodes that are in offline or resync state. All disk groups must have zero offline disks and Resync = No, by running the following command:
```
# flashgrid-cluster
```
First DB node: Stop all databases.
First DB node: Stop Oracle cluster services, by running the following command:
```
# crsctl stop cluster -all
```
All nodes: Stop the FlashGrid Diagnostics monitoring service:
```
# systemctl stop flashgrid-node-monitor
```
All nodes: Stop the FlashGrid Storage Fabric services:
```
# flashgrid-node stop
```

All nodes: Run the following command to change the MTU setting:

# nmcli connection modify 'System eth0' 802-3-ethernet.mtu 9000

All nodes: Reboot. The reboot can be done simultaneously or one node at a time.
```
# sync; sync; reboot
```
All nodes: After reboot verify that the MTU setting is configured correctly. MTU must be set to 9000 for eth0 NIC (other NICs are expected to have different MTU):
```
# ip link show dev eth0
```
First DB node: Wait until all nodes boot up, all disks are back online, and resync operations complete on all disk groups. All disk groups must have zero offline disks and Resync = No
```
# flashgrid-cluster
```