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Networks Multiple switch setup and 2.5GbE

Discussion in 'Hardware' started by wyx087, 9 Jul 2021.

  1. wyx087

    wyx087 Homeworld 3 is happening!!

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    I think I've had a switch failure. I'm currently away from home, on Wednesday evening when I was remote desktop into my home PC to configure Proxmox on my new box, everything stopped working. I was unable to connect to anything in the home. Luckily, after the scheduled routine router restart during early hours of Friday morning, I am now able to connect to a small amount of devices, all devices connected directly to the router (wired or wireless) now responds and works. This leads me to believe my 8 ports main switch has died.

    So, I'm taking this opportunity to upgrade to 2.5 GbE.

    The plan is as follow:
    From:
    Code:
                              PC               Synology NAS       HP microserver for backup 
                                 \                          \          / 
                Router ----- 8 port gigE switch ----- 5 port gigE switch 
                                 /          \ 
                         energy mon    laptops and others 
    
    TO:
    Code:
                   PC            existing Synology NAS with USB 2.5GbE       HP microserver 
                     \          /                                     \          / 
    Router ----- 2.5GbE 5 port switch ----- 5/8 port gigE switch ----- 5 port gigE switch 
                                                  /          \ 
                                         energy mon    laptops and others 
    


    Question (1) is, will traffic always take the shortest route? If I do a transfer on PC to NAS using machine name (rather than IP), will I always get the 2+GbE speed?

    Keeping in mind all switches are unmanaged and router is a consumer grade Asus AC68u.


    Because this USB dongle method is not officially supported by Synology for the NAS, I need to keep the 1GbE connection just in-case. Hence keeping the 5 port switch in the cupboard with HP microserver.

    So, capitalising on that, I'm also thinking of running another ethernet cable from router to the 5 port switch in the cupboard with the servers. So that in case of another switch failure, I can still access data at home. How would network traffic work if I basically create a ring topology layout using 3 switches and a router?

    Summary of question 2 would be, are redundancies within an ethernet network just exactly that? It wouldn't confuse data packet routing, etc? Is there any configuration required to set up this kind of redundancy?
     
  2. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

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    Having the NAS available on two NICs is likely to confuse things. I'd recommend connecting it only via 2.5gigE. If you really, really want to have it under two connections you'll want to either always use IP or set up two different DNS entries (or machine names, whatever) - server.local and server-fast.local or something. Otherwise you'll get whatever last registered itself on the network, at a guess.
     
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  3. noizdaemon666

    noizdaemon666 I'm Od, Therefore I Pwn

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    I agree with Gareth, just use the 2.5gigE or you run the risk of all sorts of tomfoolery happening. Although, you could setup the 1G NIC as a failover port, if the software allows anyway. It would need to be explicitly set like that though, rather than hoping the network figures it out for you.
     
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  4. wyx087

    wyx087 Homeworld 3 is happening!!

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    Brilliant. That's the kind of insight I'm missing.

    Okay, quick search comes up with this functionality in the NAS software:
    https://kb.synology.com/en-us/DSM/help/DSM/AdminCenter/connection_network_linkaggr?version=6
    This should configure the NAS to use 2.5GbE as active and use the standard gigE as fallback..... from the looks of it.


    So the network switches can be connected in a ring without problem?
     
  5. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

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    Not unless you're installing a token ring network. All the switches connected to the router, fine; all the switches connected in a line with the router at the end (or, really, anywhere), fine; all the switches connected together in a big Ethernet cuddle-puddle? Not fine. That's how you get a network taken down by a broadcast storm.

    (Well, once upon a time. These days the switch'd detect the problem and just switch off the affected port(s). Which is boring.)

    Make sure you only have one Ethernet cable running betwix switches, as per your diagram, and you'll be golden.
     
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  6. wyx087

    wyx087 Homeworld 3 is happening!!

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    Right okay. Thank you. Just simple A-B.

    Sounds like it needs more advanced switch and/or router at the end to configure as failover, in similar fashion as the NAS. Unmanaged switch and consumer router probably can’t do this.
     
  7. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

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    Shouldn't need anything you don't have: I'm saying you can't have two Ethernet cables running between two switches*, not that you can't have two Ethernet cables running to a single node.

    For failover, the NAS should simply keep the failover network port disabled until the active port drops - the switch doesn't need to be involved, it'd just see the device on Port 1 disappear and a new device appear on Port 2.

    * Well, yes, okay, you can if the switches support stuff like failover, aggregation, port trunking, whatever. But you'd probably know if you had a switch that did that - and they don't usually come in five-port flavours...
     
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  8. sandys

    sandys Multimodder

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    I don't know about Synology but on most NAS software I have tried you can link all network interfaces for failover and indeed have them all connected to the switch, I did this it was not a issue for Unraid or TrueNAS, can't remember Openmedia vault and whilst messing with this multi interface stuff is when I discovered that SMB multichannel was a thing and I could infact max 2 10Gb links using NVMe array in my NAS :D

    You don't need fancy switches to do it either.
     
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  9. Mister_Tad

    Mister_Tad Will work for nuts Super Moderator

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    My use case is slightly different so there's a chance that for your uses this is incorrect, but I came to the conclusion that there was no straightforward/tidy way on Synology to prioritise access between multiple interfaces. As I have it now I use 2x 10Gb for data and have 2x1Gb on a management VLAN (both LACP). I did want the other 2x 1Gb ports as a failover for data in case the 10Gb switch pooped itself or something of the sort, but by my reckoning there was no tidy way to do it whilst still guaranteeing 10G hosts would always get the 10G.

    Also, Connect switches together more than once without some form of both link aggregation and spanning tree at your peril. Network loops have brought many a network to its knees. Including my own before I realised that "Sonos Mesh" is actually based on ancient legacy STP.

    EDIT: FYI by using a USB NIC I think you may be killing your upgrade path to DSM 7
     
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  10. wyx087

    wyx087 Homeworld 3 is happening!!

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    Thanks all. In the end, I decided to abandon multi-gig ethernet for now and continue to use good ol' gigabit ethernet.
    3 reasons:
    1. USB dongle driver is very messy to setup and require intervention after reboot.
    2. HDD transfer speed is the limiting factor, won't give me double the speed as I hoped, fastest single HDD can copy file is going to be a small increment over GbE, not worth the effort of 1.
    3. the hole I had, going through a very thick external wall, won't fit a third cable (currently ethernet and power). I'd need re-run all wires to get it fit through.

    I'll wait until my next NAS upgrade to upgrade both switches and also really need a NAS with NVMe cache to make this worth well.


    As for DSM 7, I plan to wait a bit. Never been the first to charge into constant FW bugfixing updates. Especially not on my NAS holding all my data.
     

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