Proper way to use IFGroups

Dynamox has answered your question perfectly.

But, to elaborate slightly to the common questions;

LACP has a high overhead on the 2Gbe you see, so you won't get all of that, sometimes the hit is as much as 40%.

For these LACP connections to work over 2 different switches, you'll need VPc (Cisco) or Vlag (Brocade) or you'll only ever make use of one of these paths and take the LACP hit too.

DDSM has some "realtime charts" under "home", you can see the interfaces become start to be used and balanced when you add more backup streams.

"ifconfig" or "net show config" (DDOS command for the same thing) will give you a good overview of TX/RX on each interface. It can be hard work to look at this but it does give reassurance for me personally, that the interfaces are all being used and how well balanced they are over time (this often proves a complete lack of VPc enablement).

If you want to see realtime charts (of sorts) on the DD network interfaces via CLI;

"system show stats view net interval 5" - this is handy to see.

This can be enhanced to include info about DDBoost too but can be awkward on big systems to physically fit without adding columns to your SSH (putty) tool;

"system show stats view net custom-view ddboost interval 5"

With Dynamic interface groups (DIG's) you can also use ifgroups for replication.

You just need resilience for the initial connection to the DD management interface (veth0 in the example provided by Dynamox), this can be failover, rather than LACP and that too needs no special configuration on the switches at all (unless it's to be VLAN/VLAN tagged).

If you only have DDBoost, you really don't need LACP anymore.

If you have non-DDboost Net requirements, you may still need LACP, unless you have 10Gbe and that's enough to warrant failover or just the physical NIC alone.

Regards,

Jonathan

Hello, dynamox.

A question about your example. If your avamar connects to DataDomain through veth0, how can Data Domain tell to Avamar that use a link in the igfroup if veth0 is not a part of the ifgroup?

Data Domain looks at clients that connect via DDBoost protocol (whether it's Avamar, DDBoost for RMAN ..etc), decides if client's IP matches any of the defined clients.  If yes it tells client to reconnect using an IP address from the matching ifgroup. If client's IP does not match any of the defined clients it will try to use default ifgroup.  If it can't talk to default ifgroup either and ifgroup enforcement parameter is not set , it will go back to using veth0 interface for backups.

Hi Paul,

I often refer to the use of IFGroups on Data Domain appliances as "Application level aggregation" because of the lack of a physical requirement to configure the network ports. The main DNS responding interface on the Data Domain appliance is the management interface that assigns the tasks/streams to the IFGroup interfaces as they come in. This is seamless to the hosts requiring the stream connections. Also, remember that you will need the proper FW ports opened to the IFGroup interfaces to ensure that the traffic can properly flow when the client is re-directed to use the IFGroup interfaces. As an example, without SunRPC 111 in the FW rule, I found that the recovery streams all stayed on the management interface until we allowed that port on the IFGroup interfaces for the recovery client. I hope this helps clarify this for you.

Thank you all for the explanation.

In my case we have only 4 network cards. So let me see if I get this right.

vth0          10.100.4.200 (LACP with eth0a and eth5a)

eth0a

eth0b        10.100.4.201

eth5a

eth5b        10.100.4.202

Then create the ifgroup with 10.100.4.201 and 10.100.4.202 and nothing special on the configuration of those ports on the switch.

Now, we use BackupExec with the OST plugin loaded so my take is that we set the definition of the DataDomain Storage Device, but use 10.100.4.200 as the IP address of the device.

While the backup gets initialized it will be smart enough to flip and use either 10.100.4.201 or 10.100.4.202.

My only concern then will be any event in which it will use 10.100.4.200 which is also the management interface and will be difficult to connect to the DD for management.

I guess my final question will be then the configuration for the ifGroups. I have the following:

Interface Groups

default               yes    10.100.4.200

GROUP01         yes    10.100.4.202,10.100.4.203

Configured Clients
*                        default

10.100.4.0/24   GROUP01

the network segment is actually a /22 but I guess it does not let me use that or individual IP addresses so it whitelists the entire network.

Is this the proper way to do it?

Thanks all for your help!

Paul Aviles wrote: Thank you all for the explanation. In my case we have only 4 network cards. So let me see if I get this right. vth0          10.100.4.200 (LACP with eth0a and eth5a) eth0a eth0b        10.100.4.201 eth5a eth5b        10.100.4.202 Then create the ifgroup with 10.100.4.201 and 10.100.4.202 and nothing special on the configuration of those ports on the switch.

that looks good to me, and i believe you can add the IP address assigned to your veth0 to ifgroup as well (i am not sure how that would be balanced on the back-end)

Paul Aviles wrote: Now, we use BackupExec with the OST plugin loaded so my take is that we set the definition of the DataDomain Storage Device, but use 10.100.4.200 as the IP address of the device. While the backup gets initialized it will be smart enough to flip and use either 10.100.4.201 or 10.100.4.202. My only concern then will be any event in which it will use 10.100.4.200 which is also the management interface and will be difficult to connect to the DD for management.

my veth0 interface is used by applications that do not support DDBoost and i have never had issues managing DD.

Paul Aviles wrote: I guess my final question will be then the configuration for the ifGroups. I have the following: Interface Groups default               yes    10.100.4.200 GROUP01         yes    10.100.4.202,10.100.4.203 Configured Clients *                        default 10.100.4.0/24   GROUP01 the network segment is actually a /22 but I guess it does not let me use that or individual IP addresses so it whitelists the entire network. Is this the proper way to do it? Thanks all for your help!

since you only have one subnet i would use just the default ifgroup with 10.100.4.202-203, i can't think of any reason why to create a dedicated group. and then just use default * for configured clients.  Non-Ddboost clients do not understand any of this stuff so this should be for irrelevant to them.