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Change MTU on iSCSI interfaces


Ste
151 Posts
March 17, 2025, 11:44 am

Hello,

i'm trying to change the MTU to 9000 on iSCSI interfaces (eth3 and eth5), which were left to 1500 at installation time. I went to the file /opt/petasan/config/etc/network/interfaces, but i see only the management interface:

auto eth2
iface eth2 inet static
address 10.0.2.131
netmask 255.255.252.0
gateway 10.0.2.1
dns-nameservers 10.0.2.11

I guess i should add a section dedicated to eth3 and eth5, but I cannot set it as static neither dhcp, i'm afraid. Is there another way to do it in PetaSAN ?
Thanks and bye,  Ste

Last edited on March 17, 2025, 11:45 am by Ste · #1

admin
3,054 Posts
March 18, 2025, 1:07 am

network configuration is in

/opt/petasan/config/cluster_info.json

It is pretty easy to follow, but it may be easier to create a test vm, deploy it with desired network configuration then grab the above file.

/etc/network/interfaces is only used during node boot.

 

#2

Ste
151 Posts
March 26, 2025, 10:43 am

Ok, after changing this file do i need to reboot the nodes ?

Thanks, Ste

#3

admin
3,054 Posts
March 26, 2025, 3:58 pm

yes, you should also make sure you set them on switch ports and on your clients.

#4

o.sapranov
3 Posts
September 1, 2025, 2:15 pm

Hi. I have the same question.
How can I change the mtu on the iSCSI interface.
Here is my config.
Please tell me what to do.

{
"backend_1_base_ip": "172.16.10.0",
"backend_1_eth_name": "eth1",
"backend_1_mask": "255.255.255.0",
"backend_1_vlan_id": "",
"backend_2_base_ip": "",
"backend_2_eth_name": "",
"backend_2_mask": "",
"backend_2_vlan_id": "",
"bonds": [],
"default_pool": [
"cephfs",
"radosgw",
"rbd"
],
"default_pool_pgs": "256",
"default_pool_replicas": "3",
"eth_count": 3,
"jf_mtu_size": "",
"jumbo_frames": [],
"management_eth_name": "eth0",
"management_nodes": [
{
"backend_1_ip": "172.16.10.30",
"backend_2_ip": "",
"is_backup": true,
"is_cifs": true,
"is_iscsi": true,
"is_management": true,
"is_nfs": false,
"is_s3": false,
"is_storage": true,
"management_ip": "10.1.10.53",
"name": "petasan3",
"petasan_version": ""
},
{
"backend_1_ip": "172.16.10.20",
"backend_2_ip": "",
"is_backup": true,
"is_cifs": true,
"is_iscsi": true,
"is_management": true,
"is_nfs": false,
"is_s3": false,
"is_storage": true,
"management_ip": "10.1.10.52",
"name": "petasan2",
"petasan_version": ""
},
{
"backend_1_ip": "172.16.10.10",
"backend_2_ip": "",
"is_backup": true,
"is_cifs": true,
"is_iscsi": true,
"is_management": true,
"is_nfs": false,
"is_s3": false,
"is_storage": true,
"management_ip": "10.1.10.51",
"name": "petasan1",
"petasan_version": "3.2.1"
}
],
"name": "petasan",
"storage_engine": "bluestore",
"writecache_writeback_inflight_mb": ""
}

#5

admin
3,054 Posts
September 2, 2025, 5:40 pm

easiest is to  create a test vm and install PetaSAN using iso then Deloy using Create New Cluster, specifying MTU then look at the config file. You do not need to install other nodes.

 

Last edited on September 2, 2025, 5:41 pm by admin · #6