Software RAID support

[Alessandro 123]

Hi,
would be possible to add support for software RAID (mdadm) ? In some server configuration, where multiple SATA DOM are present, the ability to create a RAID-1 for PVE install without using ZFS on root partition would be nice.

PVE would be insatlled on a RAID1 and the rest of disks in a ZFS RAID.
There is no need for advanced (and memory intensive) features of ZFS for PVE.

 

[tom]

If you want to use mdraid, install Debian and on top Proxmox VE.

See also https://pve.proxmox.com/wiki/Software_RAID

 

[Alessandro 123]

That would be too complicated as I would like to also use ZFS and PVE installed automatically configure ZFS and RAID.

What would be usefull is to add support for mdadm for PVE root, not for VM storage.

 

[Alessandro 123]

With the installer is possible to create multiple ZFS RAID, in example with disk1 and disk2 as mirror for PVE and disk 3 to 8 as RAIDZ2 for VMs ?

 

[tom]

That would be too complicated as I would like to also use ZFS and PVE installed automatically configure ZFS and RAID.

What would be usefull is to add support for mdadm for PVE root, not for VM storage.

There are reasons why mdraid is not perfectly suitable (e.g. no protection against silent data corruption). therefore we not recommend or integrate mdraid in the installer. If you want raid without buying a hardware raid controller, ZFS is the only recommended way.

 

[Alessandro 123]

For the root partition with pve install, there is no need for silent data corruption protection

I'm not talking about the data partition but only the partition that host PVE/Debian

 

[tom]

For the root partition with pve install, there is no need for silent data corruption protection

So you have no problem when your server does not boot anymore and the OS partition is damaged and unrecoverable?

 

[Alessandro 123]

Yes but
1: you can reinstall in minutes with no data loss (data are on ZFS)
2. This never happened to me in 10 years.

 

[tom]

Yes but
1: you can reinstall in minutes with no data loss (data are on ZFS)

Only if you have a clear documentation of your setup and/or a backup of your configs.

2. This never happened to me in 10 years.

Yes. There is a reason why its called "silent data corruption" - you do not notice it most times, but this does not mean that it does not happen.

But anyways, you are free to use mdraid, but we do not include this in our installer due to some reasons.

 

[Alessandro 123]

But is possible, from the installer, to create a zfs raid1 with 2 disks for pve and a raidz2 with different disks for the vms?

 

[fabian]

But is possible, from the installer, to create a zfs raid1 with 2 disks for pve and a raidz2 with different disks for the vms?

no - the installer only sets up the system disk(s) and a default storage on it (no matter which storage type you use). any further storage configuration is supposed to happen later, by the admin.

 

[LnxBil]

And the ZFS memory consumption for an almost empty pool is negligible. What should be stored there?

I was - for over a decade - a regular user of mdadm but after spending time with ZFS, I will never return to mdadm. It is just too restricted in so many ways.