High availalability

high-availability

(alex) #1

Guys ive had a look through here hoping (without success) to find some useful help for my current challenge as follows - i have 2x servers each of which has nethserver installed as a VM. I like nethserver and would like to introduce some fault tollerance to accomodate site/server failure. Any suggestions in this space appreciated.

Currently all server data sits on internal disk - is there scope to migrate certain data/filesystems onto external storage (if so which filesystems?) with a view to synchronising this data with a remote storage unit (i would consider taking the servers down on a daily basis to complete this task).

Ultimately i guess my question is: where does the “application data” reside on this server and can it be easily replicated and fired up on a secondary server…


(Markus Neuberger) #2

Hi @alpreseidente,

Which virtualization do you use? I ask, because you may use it for replicating. With VMware or Proxmox you don’t have to think about, where the files are located, the whole VM is just copied…in case of emergency just start the copied vm and troubleshoot without pressure. You may even replicate from one server to another and vice versa, so you have two virtual servers and one physical may go offline and the other one has both vms on it, ready to start.

I use VMware esxi and xsibackup to push my vm images to an NFS share as snapshot backup. So you may backup any filesystem to your favourite filesystem.
Proxmox should support that too: https://pve.proxmox.com/wiki/Backup_and_Restore


(alex) #3

Hi Markuz thanks for feedback - im using qemu (on ubuntu) for virtualisation - i have no particular affinity for it other than its the road ive gone down and im trying to avoid constant changes in direction because its time consuming. I get your point about copying VMs (cloning i think). My resistance to this approach is it seems quite inefficient to take a full copy of an entire server each day rather than just copy the data that has changed and update it on the secondary server… also upon reflection if i am housing my primary and secondary nethservers in seperate buildings/locations then im reliant on network bandwidth to ship the entire image accross (i could probably get away with this now but data will inevitably grow!)

ive come from an enteprise environment so it seems instinctive to me to seperate out my data into OS/App executables/App data and treat the App data, i.e. the data thats changing daily, differently to the OS/executable data that is largely static

…im looking forward to the discussion though!


(Markus Neuberger) #4

Nethserver supports KVM/qemu with web UI, so you may replace your Ubuntu to have physical and virtual Nethservers :slight_smile:

You are able to replicate only what changed, In KVM/qemu there is block replication.
VMWare supports CBT(Changed Block Tracking)
Proxmox has storage replication

That would be possible with the virtual hard disks, just make os disks and data disks, so you may backup them differently, like data every day and os less frequently. But when able to just backup what changed, you may even do it everyday without problems.