new instal over 2 ssd in mdraid mode

[guletz]

Hello to all,


I am planning a new proxmox install like this:

4 identical nodes with different storage
- for 2 nodes I wish to use 2 ssd with different capacity (120 Gb and 64 Gb)
- I wish if it is possible to alocate let say 48 Gb / each ssd
- at the instalation I wish to use LVM at top of 2 x 48 Gb md mirror

(48 Gb ssd1 --- md mirror --- 48Gb ssd2) = LVM for /

If I can solve this problem will be very good for my setup


I can do it from proxmox installer? It is not a problem to make in advance the partitions (48 Gb). The ideea is to avoid any truble with zfs boot, as I discover in my testing period.

Thx a lot in advance!

 

[LnxBil]

The Proxmox VE installer as well as the official support states, that mdadm software raid is neither supported nor useable in the installer.

If you want to do that by yourself, just install Debian Jessie and afterwards Proxmox VE on top of that. Another solution would be to use ZFS, which is the only supported software raid supported by the installer and the Proxmox support staff.

 

[guletz]

The Proxmox VE installer as well as the official support states, that mdadm software raid is neither supported nor useable in the installer.

If you want to do that by yourself, just install Debian Jessie and afterwards Proxmox VE on top of that. Another solution would be to use ZFS, which is the only supported software raid supported by the installer and the Proxmox support staff.

Thx LnxBil. I will do it like this. It will be any problem for the cluster if the rest of the noded will be installed with vanilla proxmox installer (so 2 will be with debian and the rest of 2 will be with proxmox)?

Thx.

 

[jim.bond.9862]

I wouldn't do it this way.
you are creating a headache for yourself in terms of management in the future.

the SSDs are cheap this days.
just find a deal on 120s or 64s and get a matching pair for all servers.
and just load Proxmox with ZFS raid-1 on it.
proxmox does not support MD raid on install so it is either zfs raid-1 or do a Debian installs first and than loading Proxmox on it.
it is not that you will run Debian on the nodes, it is just that you will stat out with Debian install and then you will load the proxmox over it. at the end all nodes will run Proxmox, it will just be installed using different technique. not sure if it matters but if you go with Debian+Proxmox setup, I would use it on all nodes. it seems safer for me.

no to elaborate a bit more.
the problem here is that Proxmox installer does not support the use of MD raid on setup.
Debian installer does. hence the tip for you, if you really set on using the MD raid for your OS drive you need to do a 2 step install.
step 1 : install Debian first, use the option for manual partitioning and setup the MD raid during install.
Step 2: add proper repos and install Proxmox on top of debian. this will use whatever OS drive setup already there.

 

[guletz]

Thx. jim,

the SSDs are cheap this days.
just find a deal on 120s or 64s and get a matching pair for all servers.

Simply I can not do this. I must use what I have, nothing more! I hope I can get another 2 SSD only after 4 month, but until then I need to finish my proxmox cluster!

Debian+Proxmox setup, I would use it on all nodes. it seems safer for me.

Yes, sometimes is safer to have all the server with the same distro, but sometimes is safe to have different distro. Belive me that I have seen both situations(in some cluster enviroments).

I think that I have 2 posibilities(zfs as boot device is excluded, I like zfs but I will used as boot only after a entier year without errors on my test system), after I read your kindly post:

1.- I can use a HW raid mirror with 2x 120 Gb SSD on the first node, and 2x 64 Gb SSD on the second node(maybe not so safe ... or wise)
2.- or I can use only a single 120 Gb SSD, on both nodes, and reuse the 64 Gb SSD for zfs cache

Note: After I finish the proxmox install I will add 2x4 Tb HDD in a zfs mirror on any node

 

[jim.bond.9862]

well, frankly, if you are using ZFS anyway

Note: After I finish the proxmox install I will add 2x4 Tb HDD in a zfs mirror on any node

I would go with ZFS install. believe me I am not an avid ZFS supporter. I am not very good with ZFS myself so I can not comment on how good it is or bad it is, or anything. but if you will be running ZFS storage, why mix and match?
I have a test setup right now and ZFS raid-1 works well. granted it is a test setup and there is nothing on it, but with everything my research show , if you know how to work with zfs, it works and works well.
if you are running data store on it why do you have a problem running OS on it?

 

[guletz]

if you are running data store on it why do you have a problem running OS on it?

Because sometimes, boot with zfs can be broke. And I see this on my own. In many cases, grub is the problem or the distribution. I am run many servers with zfs, but without zfs boot(only plain mdraid), and I do not see any problem(with zfs as data disks, in various setups, including some many TB migration from let say mirror to raidz1 and then again to raidz2) in the last 4 years. I find that zfs is rock solid(at lest for me). I did not see anything that coud have the same performance/safety/usability/and so on, like zfs. And I think that I have try almost any major FS/volume-manager(for general usage) that is important(and some exotics like NILFS for example) in this area, for at least several months.