Thin provisioning in XS7

BRRABill

You need to go back and ready my LVM papers. LVM is not a filesystem.

https://mangolassi.it/topic/9767/linux-the-role-of-the-logical-volume-manager-lvm/
https://mangolassi.it/topic/9766/logical-volume-manager/

You keep saying that, and it isn't helping!!

I was going to ask if it was a confusion on my part about LVM.

scottalanmiller

Yes, you are thinking of LVM as "what's on top" but you can't use LVM, it's just an abstraction layer in the middle. It replaces the partitioning layer. So LVM instead of MBR, for example.

LVM is what provides abilities like thin provisioning, snapshots and resizing. Without LVM, you can't have those. LVM sits on top of the final block devices as presented to the OS. Then the filesystem (EXT3 in this case) goes onto the logical volume(s) created by LVM.

You can't use LVM directly, just like you can't use a partition directly.

So if you look at the block device (drive) and ask what is on it, it seems LVM. If you look from the top down you look at the filesystem (EXT3.) If you look at the stack, LVM is the piece in the middle. EXT3 is on LVM, LVM is on the RAID array.

Francesco Provino

@scottalanmiller said in Thin provisioning in XS7:

Yes, you are thinking of LVM as "what's on top" but you can't use LVM, it's just an abstraction layer in the middle. It replaces the partitioning layer. So LVM instead of MBR, for example.

LVM is what provides abilities like thin provisioning, snapshots and resizing. Without LVM, you can't have those. LVM sits on top of the final block devices as presented to the OS. Then the filesystem (EXT3 in this case) goes onto the logical volume(s) created by LVM.

You can't use LVM directly, just like you can't use a partition directly.

So if you look at the block device (drive) and ask what is on it, it seems LVM. If you look from the top down you look at the filesystem (EXT3.) If you look at the stack, LVM is the piece in the middle. EXT3 is on LVM, LVM is on the RAID array.

This is perfectly clear to me, I'm a Linux sysadmin. But I still don't get how to get a thin provisioned LOCAL SR on XS, LVM-based.

scottalanmiller

@Francesco-Provino said in Thin provisioning in XS7:

This is perfectly clear to me, I'm a Linux sysadmin. But I still don't get how to get a thin provisioned LOCAL SR on XS, LVM-based.

It's because of a funky terminology that they use. It's all LVM based. But thin provisioning is done by putting EXT3 on top of LVM and then making files representing the block devices for the individual VMs. The "LVM way" is exposing LVs directly to the VMs and letting them consume them as block devices, so it is more like a local SAN. The VMs put a filesystem directly onto the LVs in the case where they say "using LVM."

XS is very bad at being clear about what they are saying.

BRRABill

I really think that is what has thrown me for a loop.

@scottalanmiller has been working with my on LVM, and then I try to figure it out the XS inplmentation of it and it is very confusing. (To me.)

scottalanmiller

@BRRABill provided a link to this command that allows for thin provisioning...

xe sr-create host-uuid=$host_uuid content-type=user name-label="SR name" shared=false device-config:device=/dev/sdX type=ext

BRRABill

Here's a link to the whole article.

http://techblog.danielpellarini.com/sysadmin/how-to-enable-thin-provisioning-on-xenserver/

Francesco Provino

@BRRABill said in Thin provisioning in XS7:

Here's a link to the whole article.

http://techblog.danielpellarini.com/sysadmin/how-to-enable-thin-provisioning-on-xenserver/

So, nothing has changed in XS7 about thin provisioning… sadly, a plain KVM or XEN (so, the full Linux storage backend) is way ahead in flexibility, with thin-lvm, external and internal qcow (or raw) snapshot, etc.

scottalanmiller

@Francesco-Provino said in Thin provisioning in XS7:

@BRRABill said in Thin provisioning in XS7:

Here's a link to the whole article.

http://techblog.danielpellarini.com/sysadmin/how-to-enable-thin-provisioning-on-xenserver/

So, nothing has changed in XS7 about thin provisioning… sadly, a plain KVM or XEN (so, the full Linux storage backend) is way ahead in flexibility, with thin-lvm, external and internal qcow (or raw) snapshot, etc.

Yes, and will likely always remain so. Xen has always been vastly more powerful and flexible than XenServer, but lacks the distro model. XenServer is about making it packaged and easy.

Francesco Provino

@scottalanmiller said in Thin provisioning in XS7:

@Francesco-Provino said in Thin provisioning in XS7:

@BRRABill said in Thin provisioning in XS7:

Here's a link to the whole article.

http://techblog.danielpellarini.com/sysadmin/how-to-enable-thin-provisioning-on-xenserver/

So, nothing has changed in XS7 about thin provisioning… sadly, a plain KVM or XEN (so, the full Linux storage backend) is way ahead in flexibility, with thin-lvm, external and internal qcow (or raw) snapshot, etc.

Yes, and will likely always remain so. Xen has always been vastly more powerful and flexible than XenServer, but lacks the distro model. XenServer is about making it packaged and easy.

Uhm, I haven't found XS7 any easier than a plain linux distro until now, Its only big advantage is the great API that provide a nice and encapsulated method to backup VMs. But IMHO is both harder and less powerful than libvirt (with both Xen and KVM).

scottalanmiller

@Francesco-Provino said in Thin provisioning in XS7:

@scottalanmiller said in Thin provisioning in XS7:

@Francesco-Provino said in Thin provisioning in XS7:

@BRRABill said in Thin provisioning in XS7:

Here's a link to the whole article.

http://techblog.danielpellarini.com/sysadmin/how-to-enable-thin-provisioning-on-xenserver/

So, nothing has changed in XS7 about thin provisioning… sadly, a plain KVM or XEN (so, the full Linux storage backend) is way ahead in flexibility, with thin-lvm, external and internal qcow (or raw) snapshot, etc.

Yes, and will likely always remain so. Xen has always been vastly more powerful and flexible than XenServer, but lacks the distro model. XenServer is about making it packaged and easy.

Uhm, I haven't found XS7 any easier than a plain linux distro until now, Its only big advantage is the great API that provide a nice and encapsulated method to backup VMs. But IMHO is both harder and less powerful than libvirt (with both Xen and KVM).

have you played with XenOrchestra?

Francesco Provino

@scottalanmiller said in Thin provisioning in XS7:

@Francesco-Provino said in Thin provisioning in XS7:

@scottalanmiller said in Thin provisioning in XS7:

@Francesco-Provino said in Thin provisioning in XS7:

@BRRABill said in Thin provisioning in XS7:

Here's a link to the whole article.

http://techblog.danielpellarini.com/sysadmin/how-to-enable-thin-provisioning-on-xenserver/

So, nothing has changed in XS7 about thin provisioning… sadly, a plain KVM or XEN (so, the full Linux storage backend) is way ahead in flexibility, with thin-lvm, external and internal qcow (or raw) snapshot, etc.

Yes, and will likely always remain so. Xen has always been vastly more powerful and flexible than XenServer, but lacks the distro model. XenServer is about making it packaged and easy.

Uhm, I haven't found XS7 any easier than a plain linux distro until now, Its only big advantage is the great API that provide a nice and encapsulated method to backup VMs. But IMHO is both harder and less powerful than libvirt (with both Xen and KVM).

have you played with XenOrchestra?

Not yet, but in truth I really prefer a solid CLI and documentation to another fancy GUI…

DustinB3403

@Francesco-Provino said in Thin provisioning in XS7:

@scottalanmiller said in Thin provisioning in XS7:

@Francesco-Provino said in Thin provisioning in XS7:

@scottalanmiller said in Thin provisioning in XS7:

@Francesco-Provino said in Thin provisioning in XS7:

@BRRABill said in Thin provisioning in XS7:

Here's a link to the whole article.

http://techblog.danielpellarini.com/sysadmin/how-to-enable-thin-provisioning-on-xenserver/

So, nothing has changed in XS7 about thin provisioning… sadly, a plain KVM or XEN (so, the full Linux storage backend) is way ahead in flexibility, with thin-lvm, external and internal qcow (or raw) snapshot, etc.

Yes, and will likely always remain so. Xen has always been vastly more powerful and flexible than XenServer, but lacks the distro model. XenServer is about making it packaged and easy.

Uhm, I haven't found XS7 any easier than a plain linux distro until now, Its only big advantage is the great API that provide a nice and encapsulated method to backup VMs. But IMHO is both harder and less powerful than libvirt (with both Xen and KVM).

have you played with XenOrchestra?

Not yet, but in truth I really prefer a solid CLI and documentation to another fancy GUI…

XO isn't just a gui, it's a single pane of glass for everything XS.

Backup, VM management and Host control.

scottalanmiller

@Francesco-Provino said in Thin provisioning in XS7:

@scottalanmiller said in Thin provisioning in XS7:

@Francesco-Provino said in Thin provisioning in XS7:

@scottalanmiller said in Thin provisioning in XS7:

@Francesco-Provino said in Thin provisioning in XS7:

@BRRABill said in Thin provisioning in XS7:

Here's a link to the whole article.

http://techblog.danielpellarini.com/sysadmin/how-to-enable-thin-provisioning-on-xenserver/

So, nothing has changed in XS7 about thin provisioning… sadly, a plain KVM or XEN (so, the full Linux storage backend) is way ahead in flexibility, with thin-lvm, external and internal qcow (or raw) snapshot, etc.

Yes, and will likely always remain so. Xen has always been vastly more powerful and flexible than XenServer, but lacks the distro model. XenServer is about making it packaged and easy.

Uhm, I haven't found XS7 any easier than a plain linux distro until now, Its only big advantage is the great API that provide a nice and encapsulated method to backup VMs. But IMHO is both harder and less powerful than libvirt (with both Xen and KVM).

have you played with XenOrchestra?

Not yet, but in truth I really prefer a solid CLI and documentation to another fancy GUI…

Solid CLI is good, but if you are using CLI, XenServer is the wrong product for you. XenServer's purpose is the XAPI and the only good XAPI implementation is XenOrchestra.

Nothing wrong with the all CLI approach, but XenServer really has no value in that case. Xen will kick its butt.

Francesco Provino

Ok, using the ext type of storage the thin provisioning works without an issue; thanks to everybody for the answers!

scottalanmiller

And if you look, that EXT3 type is on LVM. Hence the weird confusion

BRRABill

@scottalanmiller said in Thin provisioning in XS7:

And if you look, that EXT3 type is on LVM. Hence the weird confusion

Yeah that, as I said, is what got me.

So, if you pick EXT is enables thin provisioning by default?

scottalanmiller

@BRRABill said in Thin provisioning in XS7:

@scottalanmiller said in Thin provisioning in XS7:

And if you look, that EXT3 type is on LVM. Hence the weird confusion

Yeah that, as I said, is what got me.

So, if you pick EXT is enables thin provisioning by default?
Yes. Because thin provisioning is not actually the option. It's actually just raw LVM vs file based. Files are thin provisioned. LVM raw is not. File based is being called ext3 here.