VM, storage and best practice

[llaumgui]

Hi,

I would like know if the best way is to make a big VM with all space needed or if I make a tiny VM and mount a LVM partition into ? Resize a VM is easy ?

Another question, if i don't use OpenVz, there is'nt any issue tu use ext4 ?

 

[udo]

Hi,

I would like know if the best way is to make a big VM with all space needed or if I make a tiny VM and mount a LVM partition into ? Resize a VM is easy ?

Another question, if i don't use OpenVz, there is'nt any issue tu use ext4 ?

Hi,
sorry - don't understand your first question.
For ext4: Inside the container? Or for an hostfilesystem on the pve-host? As filesystem on pve-data (/var/lib/vz)?
I use normaly lvm-storage for container and for localstorage i use the standard ext3 - never had problem with such a config. Due to fsck-times my pve-data is not so big. The big storages are lvm-storage.

Udo

 

[llaumgui]

Hi,
sorry - don't understand your first question.

I would like know, if I need a VM of 100Go, the best way is to create a VM of 100Go or create a VM of 15Go and add a LVM volume to my VM ?

For ext4: Inside the container? Or for an hostfilesystem on the pve-host? As filesystem on pve-data (/var/lib/vz)?

Inside container + pve-data

I use normaly lvm-storage for container and for localstorage i use the standard ext3 - never had problem with such a config. Due to fsck-times my pve-data is not so big. The big storages are lvm-storage.

Thx, good idea !

And for resize a VM is it easy ?

Thx

 

[udo]

I would like know, if I need a VM of 100Go, the best way is to create a VM of 100Go or create a VM of 15Go and add a LVM volume to my VM ?

I use normaly a "small" system-partition (sda, or vda for the vm on local-storage, or lvm-storage) and a additional data-partition (sdb or vdb - same type like the system-partition). Why? I can use the proxmox-backup for the system-partition and mark the big data-partition as "backup=no". The data inside the vm was backuped with bacula and the proxmox-backup is for easy recovery on an iron.

Inside container + pve-data

some people in this forum use ext4 - don't know exactly if there issues (try to use the find-option of this forum)

Thx, good idea !

And for resize a VM is it easy ?

Thx

resize is very easy, because the vm-disks are logical volumes on the hosts. Simply lvextend and your disk grow...

Udo

 

[lastguru]

Actually, there *should* be a full ext4 support including OpenVZ quotas in the newest kernel, so I suppose you can use ext4 for all purposes. I will be soon migrating to a new storage, so I will check this.

 

[llaumgui]

Thank you for you help.

Last question : If I have 300Go RAID1 + 1.2To RAID5, I install Proxmox on my RAID1 and use my RAID5 for pve-data + data and the rest of my RAID1 for backup ?

 

[udo]

Thank you for you help.

Last question : If I have 300Go RAID1 + 1.2To RAID5, I install Proxmox on my RAID1 and use my RAID5 for pve-data + data and the rest of my RAID1 for backup ?

Hi,
to split the raid1 to use it also for backup is only makable with handwork.
If you want to use your raid5 for pve-data you can simply extend your pve-vg. For a new lvm-storage you need an second partition.
If you extend your pve-vg, you can move the existing LVs, pvremove sda2, create new partitons on sda (smaller sda2 and sda3 for backup), add the new sda2 to pve-vg and move pve-root and pve-swap back.

Udo

 

[llaumgui]

Thank you for your help !

Now I have a nice server.

A new question, can I to passed a LVM "true" partition to my VM ?

 

[udo]

Thank you for your help !

Now I have a nice server.

A new question, can I to passed a LVM "true" partition to my VM ?

Hi,
should be able: use the right filter-entry in /etc/lvm/lvm.conf like this: "filter = [ "r|/dev/sdc1|", "r|/dev/sdc2|", "r|/dev/disk/|", "r|/dev/block/|", "a/.*/" ]"; in this case sdc1 and sdc2 don't used by the lvm on the host.
After that, you can assign the partition to an VM:
"ide1: /dev/sdc1"
In this case your VM see an disk without partitiontable (because it's only an partition), but lvm should have no problems with this.

Udo

 

[llaumgui]

And for the performances ? A true LVM partition is more performant that a RAW partition ? Because if the performance are equals, I mount a RAW LVM partition (it's more simple).

@udo > Thank for all your help.

 

[udo]

And for the performances ? A true LVM partition is more performant that a RAW partition ? Because if the performance are equals, I mount a RAW LVM partition (it's more simple).

@udo > Thank for all your help.

Hi,
i had no performance measuring doing with raw-partitions. With an direct assigned disk you have the disadvantage of less flexibility (no migration).
Perhaps it's not relevant for your setup, but it's very nice to have the chance with live migration - eg. disks on a san (and with the right raidcontroller/disks you get also a suitable performance).
But it's also no problem to move the content of one partition/lv later to another storage...

I think it's the best you make some benchmarks.

Udo