SAMIT: Should You Still Be Using Disk Partitions
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@Pete-S said in SAMIT: Should You Still Be Using Disk Partitions:
@scottalanmiller said in SAMIT: Should You Still Be Using Disk Partitions:
@Pete-S said in SAMIT: Should You Still Be Using Disk Partitions:
LVM is just another abstraction layer that adds nothing. Debian by default doesn't even install lvm but you could if you wanted to.
That's because it's added by default by the hypervisor.
No dear, read my post in full before replying.
I did, qcow2 is what I'm referring to. If you can resize, you have an LVM. Partitions can't be flexibly resized. To resize a partition you have to delete the partition and recreate a new one that matches the starting block. Logical volumes can be resized.
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If you skip an LVM layer inside a server, you normally provide one from the outside. File based LVM systems like Qcow2 and others allow you to do some flexible things that don't require partitions such as resizing and providing different containers as completely different drives eliminating the need for partitions inside the containers because you can create an unlimited number of logical volumes.
Qcow2 on top of XFS or ETX4, for example, is the same as an LV on top of LVM. Just fatter. LVM2 is one type of LVM that works by making a super lean filesystem and making LV files on top of that. Qcow2 doesn't create the underlying lean filesystem and relies on traditional fatter filesystems like XFS or EXT4, but has basically all the same functionality - can be copied, resized, unlimited numbers, snapshots, etc. It's an LVM without the complex management layer.
The other approach is like ZFS, where the LVM layer is built into the filesystem itself. This is essentially the LVM approach + XFS or similar, but all through a single command line to make it feel like a single entity. But the layers remain the same regardless of it we break them out to an incredible degree like making file based virtual disks, if we have a management layer that does only that like LVM2, or we integrate it all into a single entity like ZFS.
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@scottalanmiller said in SAMIT: Should You Still Be Using Disk Partitions:
If you skip an LVM layer inside a server, you normally provide one from the outside. File based LVM systems like Qcow2 and others allow you to do some flexible things that don't require partitions such as resizing and providing different containers as completely different drives eliminating the need for partitions inside the containers because you can create an unlimited number of logical volumes.
Qcow2 on top of XFS or ETX4, for example, is the same as an LV on top of LVM. Just fatter. LVM2 is one type of LVM that works by making a super lean filesystem and making LV files on top of that. Qcow2 doesn't create the underlying lean filesystem and relies on traditional fatter filesystems like XFS or EXT4, but has basically all the same functionality - can be copied, resized, unlimited numbers, snapshots, etc. It's an LVM without the complex management layer.
The other approach is like ZFS, where the LVM layer is built into the filesystem itself. This is essentially the LVM approach + XFS or similar, but all through a single command line to make it feel like a single entity. But the layers remain the same regardless of it we break them out to an incredible degree like making file based virtual disks, if we have a management layer that does only that like LVM2, or we integrate it all into a single entity like ZFS.
Well, if you extend the definition of lvm then everything is using it
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@Pete-S said in SAMIT: Should You Still Be Using Disk Partitions:
I don't even use lvm on the new kvm hypervisor setup I'm working on, where one might argue it actually makes sense.
I don't use LVM2 either, or ZFS, 99% of the time. They have their place, but typically the benefit there is that LVM is more performant. So in extreme performance cases, it can have lower overhead for storage than Qcow2. But it isn't partitions vs LVM vs nothing... it's three different LVM approaches. The fourth approach is using the LVM layer from a RAID controller. Lots of people do that, too. Same as LVM2, but done on the hardware.
The one thing that makes no sense is partitioning the servers with hard partitions and skipping both LVM2 and Qcow2 approaches. That would be so weird, both inside the VMs, but especially in the hypervisor. It would feel super awkward.
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@Pete-S said in SAMIT: Should You Still Be Using Disk Partitions:
Well, if you extend the definition of lvm then everything is using it
Everything should be using it, it's the only really logical approach in the modern world. The idea of hard partitions should have died long ago. But we saw people using it just today in an example, it's still out there in a lot of servers.
If you skip the LVM layer entirely today, you'd feel it. You'd lack snapshots, ability to resize (within reason), and all the flexibility we expect.
I know it seems weird to think about, but if you look at how LVM2, ZFS, a PERC and Qcow2 works... it's all identical under the hood. But it is all different from partitions, but the same as each other.
I think the only thing that makes it feel like these might not all be LVMs is that one of them used the name LVM2 23 years ago, and the others did not. In the Windows world they called their LVM "dynamic disks". Only on Linux and AIX did their LVM layer get called LVM or LVM-something. Everyone else gave it a product name rather than the category name.
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@scottalanmiller said in SAMIT: Should You Still Be Using Disk Partitions:
@Pete-S said in SAMIT: Should You Still Be Using Disk Partitions:
Well, if you extend the definition of lvm then everything is using it
Everything should be using it, it's the only really logical approach in the modern world. The idea of hard partitions should have died long ago. But we saw people using it just today in an example, it's still out there in a lot of servers.
If you skip the LVM layer entirely today, you'd feel it. You'd lack snapshots, ability to resize (within reason), and all the flexibility we expect.
I know it seems weird to think about, but if you look at how LVM2, ZFS, a PERC and Qcow2 works... it's all identical under the hood. But it is all different from partitions, but the same as each other.
I think the only thing that makes it feel like these might not all be LVMs is that one of them used the name LVM2 23 years ago, and the others did not. In the Windows world they called their LVM "dynamic disks". Only on Linux and AIX did their LVM layer get called LVM or LVM-something. Everyone else gave it a product name rather than the category name.
In that case physical drives are using lvm too.
Mechanical disks can remap their logical sectors to physical sectors. SSDs even more so. And NVMe drives have namespaces which maps logical blocks into different independent "drives".
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@Pete-S said in SAMIT: Should You Still Be Using Disk Partitions:
@scottalanmiller said in SAMIT: Should You Still Be Using Disk Partitions:
@Pete-S said in SAMIT: Should You Still Be Using Disk Partitions:
Well, if you extend the definition of lvm then everything is using it
Everything should be using it, it's the only really logical approach in the modern world. The idea of hard partitions should have died long ago. But we saw people using it just today in an example, it's still out there in a lot of servers.
If you skip the LVM layer entirely today, you'd feel it. You'd lack snapshots, ability to resize (within reason), and all the flexibility we expect.
I know it seems weird to think about, but if you look at how LVM2, ZFS, a PERC and Qcow2 works... it's all identical under the hood. But it is all different from partitions, but the same as each other.
I think the only thing that makes it feel like these might not all be LVMs is that one of them used the name LVM2 23 years ago, and the others did not. In the Windows world they called their LVM "dynamic disks". Only on Linux and AIX did their LVM layer get called LVM or LVM-something. Everyone else gave it a product name rather than the category name.
In that case physical drives are using lvm too.
Mechanical disks can remap their logical sectors to physical sectors. SSDs even more so. And NVMe drives have namespaces which maps logical blocks into different independent "drives".
That's fair, but you can't "use" those, in most examples. They are there, but they are effectively not there to you as an admin. But yes, that would be a storage abstraction layer, but it doesn't create volumes in most cases, those that do absolutely are LVMs and we've referred to them as that for twenty years. It used to be only in the RAID controllers that this existed, but with NVMe especially that LVM layer on the drives sometimes makes its way down to the drives themselves, too.
That's why hardware layer LVM should always be mentioned in these contexts (and I think its in the video.)
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So is this drive setup right or wrong based on partitions being obsolete?
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@JasGot said in SAMIT: Should You Still Be Using Disk Partitions:
So is this drive setup right or wrong based on partitions being obsolete?
I'd recommend using volumes instead of partitions (Dynamic) so that you have the option of modifying them later and other LVM features.
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@scottalanmiller said in SAMIT: Should You Still Be Using Disk Partitions:
I'd recommend using volumes instead of partitions (Dynamic) so that you have the option of modifying them later and other LVM features.
So this is better?
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@JasGot yup. One of the really nice features of Windows is that they can often insert an LVM layer without a lot of manual effort. On Linux that would be a pain in the butt after the fact.
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@travisdh1 said in SAMIT: Should You Still Be Using Disk Partitions:
Microsoft's Volume Management is handled in Storage Spaces.
I misspoke, even in the straight Dynamic Volumes today (since Windows 8 and Server 2012) LDM was replaced by SS as the LVM manager.
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In a Windows world, it seems it would be better to create a Storage Space, because it gives you the flexibility to extend the storage instead of having to add/mount another virtual drive if you were to run out of space.
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@Fredtx said in SAMIT: Should You Still Be Using Disk Partitions:
In a Windows world, it seems it would be better to create a Storage Space, because it gives you the flexibility to extend the storage instead of having to add/mount another virtual drive if you were to run out of space.
Exactly. Same logic applies universally, always best to have that flexibility on your platform. It has no real overhead, but protects against the unknown.
