Cisco SG500-28P Switches & Ha (High Availability)

Howdy folks so i got two Cisco SG500 switches at Christmas I’ve been planning upgrading to switches that supports Stacking for Ha (High Availability) as I do Server to Server Communication using iSCSI and two Nodes that runs XCP-ng as i run crucial services on the VDN Network i need High Availability Switches. My old Switches i had were a Cisco SG300-28P & a Linksys SWR2008P 8 Port POE Switch, both Switches were trunked with LACP (Link Aggregation Control Protocol) although this worked there was no redundancy there so if the Cisco SG300-28P switch went offline the whole network would go offline and Server to Server Communication would be completely broken, this is not good for SAN Networks and SAN Servers so all of my crucial VMs would go offline causing things like Databases to be corrupt and VMs etc.

Now it was deciding time on what to go with with 2 Non POE Switches that supports stacking either via dedicated Stack Port like on the Catalyst Switches or Stacking Ports via SFP Ports like on the SG Series Stackable Switches, and use my old Linksys POE Switch and use more rack space this way i would have Ha for 2 switches and a separate switch for POE Devices like Access Points, Cameras and IP VoIP Phones etc or go with Catalyst Switches or go with two switches that supports Stacking and POE. looked around and decided to go with the SG500 Series POE Switches only because I’ve had good reliability with these switches and great to work with. So i picked up 2 Cisco SG500-28P 28 for £96.99 each on Christmas day which i though was a great a deal so my Christmas Money was spent like that LOL.

Now lets get onto the Configuration which is the interesting bit,

So we need to configure the Switches as a Master and a Backup/Active Fail over, with these switches its quite easy just plugging in the SFP+ Cable to G27/S3 on Master Switch then on the second Switch G28/S4 makes the switches automatically configure Master and Backup this is called Native Stack. Now why do i say SFP+ reason being on the Cisco SG500-28P both Stackable Ports runs at 5G as well as 1G, the cable i used between both switches is H! 10Gb/s SFP+ DAC Cable 0.5m i got two of these as the second switch is connected back to the Master Switch using Port G27/S3 on the second switch to G28/S4 on Master Switch this then will make two links as a fail over i.e if the transceiver or cable goes back on either of the switches the link between both switches will still be there due to second SFP+ Cable. You can also stack using the G25/S1 & G28/S2 Ports but i recommend using dedicated Stacking SFP+ Ports.

At this point the Switches has automatically decided what switch wants to be Master and Backup/Active Fail over but i prefer to manually configuring the Stack this why you know what Switch is which is the stack. So under Administration -> System Mode and Stack Management set the Master to Unit 1 then Click on the second switch above Unit View and Stack Port Configuration and configure that to be the second unit, also recommend setting Unit 1 and 2 Stack Connection Speed to 5G providing you are using a SFP+ DAC or Fibre Transceiver. Now the Switches are Configured as Master and Active/ Failover. On Unit 1 and Unit 2 we create LAGG Interfaces and assign two Ports to each LAGG Interface.

For the Server side we need to configure a LAGG/LACP Interface so you will require something like a HP NC360T Dual Port or a HP NC364T Quad Networking card or if you have a Server it will have either 2 or 4 LAN Ports, then we bring a two Ethernet Cables to Master Switch then another 2 Ethernet Cables to the Second Switch by doing this we then create our redundancy so if Master Switch goes offline the second switch will reboot then switch to Master and the 2 links in the LAGG interface will still be active on the second switch. We do this for each of the Servers, Firewalls etc.

When i was testing this on my Servers i was a bit worried because i had some VMs running and i pulled the plug on Master Switch then the second switch powered off which worried me because of the SAN Network but it didn’t even noticed that the switch went offline as its a instant switch from Active/Backup to Master. When pulling the plug on second switch the Network remains online but of course it runs half of the speed.

Here are some of the pictures of the configuration,

Before i started testing,

Configuration of the Switches,




I hope you enjoyed reading through this and learnt how Ha is configured on the Cisco SG500 Stackable switch.


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