Agent and Agentless Backups
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@obsolesce said in Agent and Agentless Backups:
It comes down to a lot of factors and to simply say agent-based backups should always be used I think is not a good statement.
And it was never said, nothing is an "always use". However, agent based backups are probably the more common use case. Agentless requires a very niche scenario to work, or to work alone without agents added on. Agents work in nearly all scenarios.
There aren't as many factors as people often state, which is part of my goal here. So many factors that people believe drive then to agentless aren't really valid factors - like cost, licensing approach, restore capabilities, change block tracking, etc.
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@obsolesce said in Agent and Agentless Backups:
If you are doing server images and/or use something like SaltStack for example that can make agent installation and configuration automated and easy, then sure.
Even without something like that, what situation is there where agent deployments is hard or cumbersome? Salt is one answer, sure, and a great one, I agree. But Group Policy, system images, or if you have only one or two VMs, just manual installs. Agent installations are typically so easy that no one ever thinks about them.
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@scottalanmiller said in Agent and Agentless Backups:
@obsolesce said in Agent and Agentless Backups:
Preference on whether or not you would rather simply restore a VM as a whole to a host of choice (or in the cloud), versus creating a new virtual machine and configuring it, then booting to a restore image so you can restore the agent-based backup... also a factor.
No, also not a factor. Both agent based and agentless do both of these options. That's why I didn't bring these things up. So many of the assumed benefits of agentless backups are myths. Lots of agent based backups do this stuff.
How does an agent installed in a VM back up the VM as a whole? That doesn't make sense. You would still need to re-create a blank VM on the host, and after that, restore the VM data from backup as if it was a physical box.
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@obsolesce said in Agent and Agentless Backups:
@scottalanmiller said in Agent and Agentless Backups:
@obsolesce said in Agent and Agentless Backups:
Preference on whether or not you would rather simply restore a VM as a whole to a host of choice (or in the cloud), versus creating a new virtual machine and configuring it, then booting to a restore image so you can restore the agent-based backup... also a factor.
No, also not a factor. Both agent based and agentless do both of these options. That's why I didn't bring these things up. So many of the assumed benefits of agentless backups are myths. Lots of agent based backups do this stuff.
How does an agent installed in a VM back up the VM as a whole? That doesn't make sense. You would still need to re-create a blank VM on the host, and after that, restore the VM data from backup as if it was a physical box.
They really can do that
It's been something that agent based backups have been able to do for a really long time. -
@scottalanmiller said in Agent and Agentless Backups:
@obsolesce said in Agent and Agentless Backups:
@scottalanmiller said in Agent and Agentless Backups:
@obsolesce said in Agent and Agentless Backups:
Preference on whether or not you would rather simply restore a VM as a whole to a host of choice (or in the cloud), versus creating a new virtual machine and configuring it, then booting to a restore image so you can restore the agent-based backup... also a factor.
No, also not a factor. Both agent based and agentless do both of these options. That's why I didn't bring these things up. So many of the assumed benefits of agentless backups are myths. Lots of agent based backups do this stuff.
How does an agent installed in a VM back up the VM as a whole? That doesn't make sense. You would still need to re-create a blank VM on the host, and after that, restore the VM data from backup as if it was a physical box.
They really can do that
It's been something that agent based backups have been able to do for a really long time.You'll have to show me an example, I've not seen it... unless we are misunderstand each other here. I find it hard to believe.
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Do you mean that the agent on teh VM makes contact with the hypervisor to backup itself at the host level?
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@obsolesce said in Agent and Agentless Backups:
Do you mean that the agent on teh VM makes contact with the hypervisor to backup itself at the host level?
No need to back up at the host level. You can get the entire VM from inside the VM. Change Block Tracking, Snapshots and similar tools have made this possible since the 1990s (very end of.)
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@scottalanmiller said in Agent and Agentless Backups:
@obsolesce said in Agent and Agentless Backups:
Do you mean that the agent on teh VM makes contact with the hypervisor to backup itself at the host level?
No need to back up at the host level. You can get the entire VM from inside the VM. Change Block Tracking, Snapshots and similar tools have made this possible since the 1990s (very end of.)
Pull your head out of your ass. That is not what he is stating.
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@obsolesce said in Agent and Agentless Backups:
@scottalanmiller said in Agent and Agentless Backups:
@obsolesce said in Agent and Agentless Backups:
Preference on whether or not you would rather simply restore a VM as a whole to a host of choice (or in the cloud), versus creating a new virtual machine and configuring it, then booting to a restore image so you can restore the agent-based backup... also a factor.
No, also not a factor. Both agent based and agentless do both of these options. That's why I didn't bring these things up. So many of the assumed benefits of agentless backups are myths. Lots of agent based backups do this stuff.
How does an agent installed in a VM back up the VM as a whole? That doesn't make sense. You would still need to re-create a blank VM on the host, and after that, restore the VM data from backup as if it was a physical box.
The answer is they don't. You have to recreate the VM and then restore.
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@obsolesce said in Agent and Agentless Backups:
@scottalanmiller said in Agent and Agentless Backups:
@obsolesce said in Agent and Agentless Backups:
Preference on whether or not you would rather simply restore a VM as a whole to a host of choice (or in the cloud), versus creating a new virtual machine and configuring it, then booting to a restore image so you can restore the agent-based backup... also a factor.
No, also not a factor. Both agent based and agentless do both of these options. That's why I didn't bring these things up. So many of the assumed benefits of agentless backups are myths. Lots of agent based backups do this stuff.
How does an agent installed in a VM back up the VM as a whole? That doesn't make sense. You would still need to re-create a blank VM on the host, and after that, restore the VM data from backup as if it was a physical box.
Okay, so there is a mix here. Agent CAN back up as a whole. That it can do. All that I know (there might be exceptions, and there definitely can be, the tech is there but I doubt anyone cares) handle restores by loading a restore ISO and it then restores the VM. Yes, you create a blank to install into, but that can be automated making it the same as agentless, because that's what agentless is doing, too.
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Pretty sure Datto does this, but I've not used it. But I know that it does agents, and does instant recovery without recreating any VMs. They've been doing that a long time.
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Ah, Datto has added agentless now, but it was doing this before adding that.
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@scottalanmiller said in Agent and Agentless Backups:
@jaredbusch said in Agent and Agentless Backups:
@scottalanmiller said in Agent and Agentless Backups:
Agent based has to be written for each OS in use, but today the number of broadly deployed OSes is much smaller than the number of deployed hypervisors. For production servers Linux, Windows, Solaris, FreeBSD and AIX are essentially all that there are. With Linux and Windows representing nearly all deployed servers. For hypervisors, we have to consider not only the base products but resulting variants so the base products like KVM, Xen, Hyper-V, and VMware ESXi (plus type 2s perhaps), plus appliances like Scale, Nutanix, Simplivity, etc. and then cloud vendors like AWS, Vultr, Digital Ocean, Linode, etc. The range of needed support is far bigger and no vendor has broadly tackled this market.
Rose colored glasses in action if I ever saw it.
In what way? Very realistic.
You are painting agents in a magic light to suit your argument.
You toss out "Linux" under the agent based strength like it is a thing when it most certainly is not. Let's look at Veeam. Their agent works on "Windows" server and desktop versions. And the "Linux" agent works on deb and rpm based systems. That is a far cry from your magic everything. Also we know for a fact that 6 months ago it did not work on current Fedora systems.
Then Unitrends has an entire breakdown for all the various ways you have to setup the agent to work
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When it comes to the agentless argument you then throw out cloud providers mixing them in with hypervisors solutions when that is an entirely different segment.
There are Type 1 solutions and the HCI solutions and then the cloud solutions.
Cloud solutions should leverage the cloud providers infrastructure. Most of them have an API of some sort to let you handle backing up your services if you need full backups. Moving things to places like this though should generally move to stateless control and only backing up of the data separately, etc.
HCI solutions have their own backup backed in also. Scale's solution work nice from what I have witnessed.
Type 2 should never be considered.
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@jaredbusch said in Agent and Agentless Backups:
@scottalanmiller said in Agent and Agentless Backups:
@jaredbusch said in Agent and Agentless Backups:
@scottalanmiller said in Agent and Agentless Backups:
Agent based has to be written for each OS in use, but today the number of broadly deployed OSes is much smaller than the number of deployed hypervisors. For production servers Linux, Windows, Solaris, FreeBSD and AIX are essentially all that there are. With Linux and Windows representing nearly all deployed servers. For hypervisors, we have to consider not only the base products but resulting variants so the base products like KVM, Xen, Hyper-V, and VMware ESXi (plus type 2s perhaps), plus appliances like Scale, Nutanix, Simplivity, etc. and then cloud vendors like AWS, Vultr, Digital Ocean, Linode, etc. The range of needed support is far bigger and no vendor has broadly tackled this market.
Rose colored glasses in action if I ever saw it.
In what way? Very realistic.
You are painting agents in a magic light to suit your argument.
You toss out "Linux" under the agent based strength like it is a thing when it most certainly is not. Let's look at Veeam. Their agent works on "Windows" server and desktop versions. And the "Linux" agent works on deb and rpm based systems. That is a far cry from your magic everything. Also we know for a fact that 6 months ago it did not work on current Fedora systems.
Then Unitrends has an entire breakdown for all the various ways you have to setup the agent to work
Those are pretty huge sets of coverage. No agentless system comes close to that. Especially when you consider that some of those, like Mac, have to be physical or seen as physical, and some, like HP-UX use a virtualization that no agentless exists for.
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@jaredbusch said in Agent and Agentless Backups:
When it comes to the agentless argument you then throw out cloud providers mixing them in with hypervisors solutions when that is an entirely different segment.
Not really, when you are using agents, and doing hybrid cloud, or unified disparate backup, that all "just works." There are companies that want to move from on prem to cloud and back, and in fact this is a huge push from the Windows world (and the Starwind one) and agent based is important for that.
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@jaredbusch said in Agent and Agentless Backups:
Cloud solutions should leverage the cloud providers infrastructure. Most of them have an API of some sort to let you handle backing up your services if you need full backups. Moving things to places like this though should generally move to stateless control and only backing up of the data separately, etc.
"Should", I agree. but once we are stateless, why do we use agent based OR agentless backups? Neither tends to make sense at that point once we can create fresh without needing a backup mechanism at all, only the configuration system. And data backups, when it is pure data, while either agent or agentless could do it, is often far more efficient and standard to use native tools because the data set is generally so isolated.
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@scottalanmiller said in Agent and Agentless Backups:
No agentless system comes close to that.
What do you mean? Agentless means the VM can have any OS you can dream up and it'll be backed up at the host level as a whole VM, unlike agent-based backup.
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@obsolesce said in Agent and Agentless Backups:
@scottalanmiller said in Agent and Agentless Backups:
No agentless system comes close to that.
What do you mean? Agentless means the VM can have any OS you can dream up and it'll be backed up at the host level as a whole VM, unlike agent-based backup.
Really? Do AIX or HP-UX then?
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Agentless backups still require hooks into the OS to truly function. It's just that those hooks come from PV drivers on the platform, not from agents. It's all still there in the code, though. Agentless isn't magic, neither are agents. Both have limitations, lots of them. Agentless can force a non-stable snap of anything running on the platform but you have to accept:
- The limitation of the platform (e.g. no physical, only AMD64, no cloud, etc.)
- That the backups aren't meant to be consistent.
The first is fine, if it meets your needs. The second violates a basic principle of take backups.
