Linux: BtrFS
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@scottalanmiller said in Linux: BtrFS:
@stacksofplates said in Linux: BtrFS:
Why are you not using logical volumes? that is both a general Linux best practice as well as the backup method for KVM.
Here we go. Clearly I was responding to why it made no sense for him to be removing LVM. It in no way was a recommendation to use this as the backup. You changed the context.
It is the backup method for KVM. But I didn't recommend it, there. Also notice that this is FIVE years old. Half a decade. Saying that I'm inconsistent over half a decade is a bit extreme. I've leaned heavily away from image based backups over half a decade, but even back then when I normally recommended them, I didn't recommend it here.
No, I didn't change the context because the context was never "I want to remove logical volumes". He didn't have it implemented yet. How is saying it is "the backup method for KVM" not recommending it.
This would all be half believable if the very next post you made wasn't a script doing exactly what I described. Suspending the VM and taking a snapshot of the logical volume.
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@stacksofplates said in Linux: BtrFS:
No, I didn't change the context because the context was never "I want to remove logical volumes". He didn't have it implemented yet. How is saying it is "the backup method for KVM" not recommending it.
Because it simply isn't. The sky is blue does not recommend that you go flying. I'm totally lost how you see me making a factual statement as being a recommendation. The two are unrelated.
I DID recommend that he have LVM, because that's just best practice. But my point was that he had installed Linux without it, which I would never recommend doing.
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@scottalanmiller said in Linux: BtrFS:
You have to look at the context of the original thread, as well. Just helping someone who was trying to figure out how to do a specific task, in a lab, long ago. He wanted a specific thing. And tools like we have today otherwise were not the same or as mature or free or whatever either.
For example, if this quote was from before good, enterprise agents were available for free or DevOps tools were wisely known or free, the context has to be understood as working with what he had at the time. Veeam agents and DevOps tools, for example, have significantly changed what good looks like in a lot of scenarios.
And you never do this any other time. You dig until you find out why they are doing something incorrectly, and have chastised people for just giving answers. You've also told people that they should be using the image files vs block storage when possible, but never mentioned it here. Again, none of the evidence you are providing points to the fact that you didn't think this was the correct way to do it.
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@scottalanmiller said in Linux: BtrFS:
@stacksofplates said in Linux: BtrFS:
No, I didn't change the context because the context was never "I want to remove logical volumes". He didn't have it implemented yet. How is saying it is "the backup method for KVM" not recommending it.
Because it simply isn't. The sky is blue does not recommend that you go flying. I'm totally lost how you see me making a factual statement as being a recommendation. The two are unrelated.
I DID recommend that he have LVM, because that's just best practice. But my point was that he had installed Linux without it, which I would never recommend doing.
Ah so you said it's the back up method, but didn't clarify that it's not the recommended method (which we all know you would never leave that out). So again, I don't believe that you didn't fully intend this as a recommendation.
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Let me give another example: the default filesystem is Suse is BtrFS.
Under no circumstances does that mean that I just recommend that you use BtrFS on Suse. If that were true, things like factsheets and datasheets would be sets of recommendations rather than lists of specs.
If I said "and you should use it" or "and I recommend it" then that would be a recommendation.
The reason that I was so adamant there is because you should not be installing Linux without it. The OP was about how he hadn't installed LVM, I responded primarily to that. The mentioning of it being useful for KVM was not even the focus but an offhand remark.
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Similarly... Windows has recently introduced ReFS.
Again, just information, not a recommendation. In fact, I'd almost never recommend ReFS. NTFS is generally better.
Of course, half a decade from now, that might change as other factors change around it.
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@scottalanmiller said in Linux: BtrFS:
Let me give another example: the default filesystem is Suse is BtrFS.
Under no circumstances does that mean that I just recommend that you use BtrFS on Suse. If that were true, things like factsheets and datasheets would be sets of recommendations rather than lists of specs.
If I said "and you should use it" or "and I recommend it" then that would be a recommendation.
The reason that I was so adamant there is because you should not be installing Linux without it. The OP was about how he hadn't installed LVM, I responded primarily to that. The mentioning of it being useful for KVM was not even the focus but an offhand remark.
No it wasn't, omg. The thread is titled "What is the best method for making backups of KVM virtual machines." Come on......
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This part is critical: "I'm testing kvm on centos 6.2 and I need to learn how to make backups that I can spin up if needed."
He wanted a backup "that could be spun up", so only images applied.
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@scottalanmiller said in Linux: BtrFS:
Similarly... Windows has recently introduced ReFS.
Again, just information, not a recommendation. In fact, I'd almost never recommend ReFS. NTFS is generally better.
Of course, half a decade from now, that might change as other factors change around it.
Certainly not if you want disk quotas (outside of FSRM) and EFS built in. Haven't tried out the resiliency aspect yet though.
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@scottalanmiller said in Linux: BtrFS:
Similarly... Windows has recently introduced ReFS.
Again, just information, not a recommendation. In fact, I'd almost never recommend ReFS. NTFS is generally better.
Of course, half a decade from now, that might change as other factors change around it.
The amount of time has nothing to do with it. It's exactly the same process then as to now. If you need to make a full image backup of a VM and it's on a logical volume, then the best method is to suspend the VM and take a LV snapshot. It's exactly the same five years later.
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@scottalanmiller said in Linux: BtrFS:
This part is critical: "I'm testing kvm on centos 6.2 and I need to learn how to make backups that I can spin up if needed."
He wanted a backup "that could be spun up", so only images applied.
Doesn't matter. That's not what the OP is about at all. It is an important part, but not what it is about. That's not up for debate in any way.
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@stacksofplates said in Linux: BtrFS:
@scottalanmiller said in Linux: BtrFS:
Similarly... Windows has recently introduced ReFS.
Again, just information, not a recommendation. In fact, I'd almost never recommend ReFS. NTFS is generally better.
Of course, half a decade from now, that might change as other factors change around it.
The amount of time has nothing to do with it. It's exactly the same process then as to now. If you need to make a full image backup of a VM and it's on a logical volume, then the best method is to suspend the VM and take a LV snapshot. It's exactly the same five years later.
Sure, I agree. If you need to make a full image backup, which was the context of the question five years ago and not at all the context of the portion of this thread that you are discussing.
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@stacksofplates said in Linux: BtrFS:
@scottalanmiller said in Linux: BtrFS:
This part is critical: "I'm testing kvm on centos 6.2 and I need to learn how to make backups that I can spin up if needed."
He wanted a backup "that could be spun up", so only images applied.
Doesn't matter. That's not what the OP is about at all. It is an important part, but not what it is about. That's not up for debate in any way.
How do his requirements not matter?
They are important enough to define the answer, clearly.
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@scottalanmiller said in Linux: BtrFS:
@stacksofplates said in Linux: BtrFS:
@scottalanmiller said in Linux: BtrFS:
This part is critical: "I'm testing kvm on centos 6.2 and I need to learn how to make backups that I can spin up if needed."
He wanted a backup "that could be spun up", so only images applied.
Doesn't matter. That's not what the OP is about at all. It is an important part, but not what it is about. That's not up for debate in any way.
How do his requirements not matter?
They are important enough to define the answer, clearly.
Stop changing the subject. You know I meant it doesn't matter in reference to this:
The reason that I was so adamant there is because you should not be installing Linux without it. The OP was about how he hadn't installed LVM, I responded primarily to that. The mentioning of it being useful for KVM was not even the focus but an offhand remark.
You said the post was about how he hadn't installed LVM. It wasn't, it was about backing up KVM machines. The fact he mentioned not having logical volumes does not matter in the sense that you said it was about him not having LVM installed. IT wasn't about that, it's not up for debate. It was an important part because you should have it installed, but it was not the point of the thread. You never said, you should be using an agent because I don't recommend taking snapshots of logical volumes. You told him to set up logical volumes and that's how KVM machines are backed up, without mentioning any other ways to do it.
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@stacksofplates you left out the part where I "recommended" a non-LVM based backup solution for the OP on that old thread and got the BA for it. I use "recommended" loosely as it was just a search for a free tool that would work for him to get what he needed and would not require LVM as he did not have it. That, too, was not a recommendation, it was simply telling him about a tell.
You can't read into every response to a thread as a recommendation or personal endorsement unless it is stated as such. If we did, we'd have to also assume that I had recommended not installing LVM, because he didn't but I still answered, or that I was recommending KVM (which might be great, but I certainly didn't promote it in any way.) There is no end to what we could read in. I simply provided some information, guidance and the accepted BA which did not involve LVM.
If we equally read into my BA response, we'd take away that I had recommended against LVM on that thread. In reality, I didn't recommend any backup style at all, only that LVM not be avoided during installation so that options would be available later.
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@scottalanmiller said in Linux: BtrFS:
@stacksofplates you left out the part where I "recommended" a non-LVM based backup solution for the OP on that old thread and got the BA for it. I use "recommended" loosely as it was just a search for a free tool that would work for him to get what he needed and would not require LVM as he did not have it. That, too, was not a recommendation, it was simply telling him about a tell.
You can't read into every response to a thread as a recommendation or personal endorsement unless it is stated as such. If we did, we'd have to also assume that I had recommended not installing LVM, because he didn't but I still answered, or that I was recommending KVM (which might be great, but I certainly didn't promote it in any way.) There is no end to what we could read in. I simply provided some information, guidance and the accepted BA which did not involve LVM.
If we equally read into my BA response, we'd take away that I had recommended against LVM on that thread. In reality, I didn't recommend any backup style at all, only that LVM not be avoided during installation so that options would be available later.
Ya that's using LVM. Nice try.
Direct quote from the site you linked (the python script I'm talking about)
I use it to backup running virtual machines in this way: first, suspend the virtual machine (for a short while), then create a snapshot of the LVM used as storage by the virtual machine, then resume the virtual machine so it can continue running without almost no downtime (taking a LVM snapshot is very fast!)
It does exactly what you just said you didn't recommend.
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@stacksofplates said in Linux: BtrFS:
@scottalanmiller said in Linux: BtrFS:
@stacksofplates you left out the part where I "recommended" a non-LVM based backup solution for the OP on that old thread and got the BA for it. I use "recommended" loosely as it was just a search for a free tool that would work for him to get what he needed and would not require LVM as he did not have it. That, too, was not a recommendation, it was simply telling him about a tell.
You can't read into every response to a thread as a recommendation or personal endorsement unless it is stated as such. If we did, we'd have to also assume that I had recommended not installing LVM, because he didn't but I still answered, or that I was recommending KVM (which might be great, but I certainly didn't promote it in any way.) There is no end to what we could read in. I simply provided some information, guidance and the accepted BA which did not involve LVM.
If we equally read into my BA response, we'd take away that I had recommended against LVM on that thread. In reality, I didn't recommend any backup style at all, only that LVM not be avoided during installation so that options would be available later.
Ya that's using LVM. Nice try.
Direct quote from the site you linked (the python script I'm talking about)
I use it to backup running virtual machines in this way: first, suspend the virtual machine (for a short while), then create a snapshot of the LVM used as storage by the virtual machine, then resume the virtual machine so it can continue running without almost no downtime (taking a LVM snapshot is very fast!)
It does exactly what you just said you didn't recommend.
Are you sure? I looked in the code and the code made a point of LVM being added later (in the 2011 notes) and sure looked like LVM was only one of the methods supported. It specifically says in the code that some features are only if using LVM. Would be weird if that was the only option.
The part you quoted was someone else talking about how they use the script, they likely had LVM so use it in that way.
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This person definitely got the opposite impression that you did from my comments in that post.
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Here is the code itself, rather than a third party discussing it:
# These files are writen in a temporary backup dir. Everything is done # in order to minimize donwtime of the guest. For example, it takes # a snapshot of the block devices (if backed with LVM) so the guest is # just paused for a couple of seconds. Once this is done, the guest is # resumed, and the script starts to dump the snapshot.That wording sure makes it sound like LVM is only an optional method, not the sole one.
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@scottalanmiller said in Linux: BtrFS:
@stacksofplates said in Linux: BtrFS:
@scottalanmiller said in Linux: BtrFS:
@stacksofplates you left out the part where I "recommended" a non-LVM based backup solution for the OP on that old thread and got the BA for it. I use "recommended" loosely as it was just a search for a free tool that would work for him to get what he needed and would not require LVM as he did not have it. That, too, was not a recommendation, it was simply telling him about a tell.
You can't read into every response to a thread as a recommendation or personal endorsement unless it is stated as such. If we did, we'd have to also assume that I had recommended not installing LVM, because he didn't but I still answered, or that I was recommending KVM (which might be great, but I certainly didn't promote it in any way.) There is no end to what we could read in. I simply provided some information, guidance and the accepted BA which did not involve LVM.
If we equally read into my BA response, we'd take away that I had recommended against LVM on that thread. In reality, I didn't recommend any backup style at all, only that LVM not be avoided during installation so that options would be available later.
Ya that's using LVM. Nice try.
Direct quote from the site you linked (the python script I'm talking about)
I use it to backup running virtual machines in this way: first, suspend the virtual machine (for a short while), then create a snapshot of the LVM used as storage by the virtual machine, then resume the virtual machine so it can continue running without almost no downtime (taking a LVM snapshot is very fast!)
It does exactly what you just said you didn't recommend.
Are you sure? I looked in the code and the code made a point of LVM being added later (in the 2011 notes) and sure looked like LVM was only one of the methods supported. It specifically says in the code that some features are only if using LVM. Would be weird if that was the only option.
The part you quoted was someone else talking about how they use the script, they likely had LVM so use it in that way.
The part I posted was the same thing you posted. It was written in 2010. So unless he's a time traveler, that's how it works.
