Repurpose small UnRaid server

[oguime]

Hi,

I want to repurpose a small UnRaid server to play with ProxMox and intend to run ordinary apps like HomeAssistant, UniFi controller, SMB shares and an occasional Windows VM and SQL Server.

It is a I5 7400 with 32GB, 1 240GB SDD, 2x 3 TB WD Reds. Can use a 2TB Seagate also, but don't want to buy new hardware right now.

Initially installed on the SSD, but was thinking if I could configure a ZFS pool with the 2 3TB WD and use the SSD as cache instead...

Any thoughts?

Thanks,
Gilson

 

[Dunuin]

Hi,

I want to repurpose a small UnRaid server to play with ProxMox and intend to run ordinary apps like HomeAssistant, UniFi controller, SMB shares and an occasional Windows VM and SQL Server.

It is a I5 7400 with 32GB, 1 240GB SDD, 2x 3 TB WD Reds. Can use a 2TB Seagate also, but don't want to buy new hardware right now.

Initially installed on the SSD, but was thinking if I could configure a ZFS pool with the 2 3TB WD and use the SSD as cache instead...

SSD cache for ZFS is in most cases not that usefull.
L2ARC read cache is only useful if you run out of memory for your ARC and if you do, you should buy more RAM first until RAM is maxex out.
SLOG/ZIL write cache is working for sync writes ONLY but NOT for async writes. Could help if you want to run the SQL server from HDDs but most things like SMB and so on are async writes which can't be cached. And if a SLOG SSD dies on an power outage you loose all your data.
SSD as "Special device" to store small files and meta data is possible, but if you SSD dies you loose all data on that HDDs to.

And if that 240GB SSD isn't a decent enterprise/datacenter grade SSD it may die within months because of wear out.
And I wouldn't run a SQL DB from a consumer SSD. These don't have powerloss protection and without that they can't use their RAM cache for sync writes, like a DB does, and because of that you get an incredible write amplification.
For example: Your SQL DB writes 3600x 8KB per hour and your SSD needs to write 3600x 1MB per hour to the flash to store this because the cache cant be used to optimize the writes.

 

[oguime]

SSD cache for ZFS is in most cases not that usefull.
L2ARC read cache is only useful if you run out of memory for your ARC and if you do, you should buy more RAM first until RAM is maxex out.
SLOG/ZIL write cache is working for sync writes ONLY but NOT for async writes. Could help if you want to run the SQL server from HDDs but most things like SMB and so on are async writes which can't be cached. And if a SLOG SSD dies on an power outage you loose all your data.
SSD as "Special device" to store small files and meta data is possible, but if you SSD dies you loose all data on that HDDs to.

And if that 240GB SSD isn't a decent enterprise/datacenter grade SSD it may die within months because of wear out.
And I wouldn't run a SQL DB from a consumer SSD. These don't have powerloss protection and without that they can't use their RAM cache for sync writes, like a DB does, and because of that you get an incredible write amplification.
For example: Your SQL DB writes 3600x 8KB per hour and your SSD needs to write 3600x 1MB per hour to the flash to store this because the cache cant be used to optimize the writes.

Hi Dunuin,

It is indeed a consumer grade SDD. Should I use the 2x 3TB HDD only? Or use the SDD to boot ProxMox?

Thanks,
Gilson

 

[bobmc]

Doesn't seem a bad starting point, could do with a few more cores or hyperthreading but it is what you have. You could reserve a small partition on the SSD for cache if you like but I don't think you'll see a great benefit in this kind of setup. Personally, I haven't seen any problems with SSD wear-out and if it's just for light duties you will probably be OK.

I suspect your SQL use will be light duties also, so again your use case may not be an issue, but it does pay to be aware of any potential issues.

Your main problem is maybe HomeAssistant as the recommendation seems to be to run it under docker. So you'd have to setup docker on Proxmox first.

Install Samba on the proxmox host for SMB shares and the Unifi controller runs fine as a container.

 

[Dunuin]

Hi Dunuin,

It is indeed a consumer grade SDD. Should I use the 2x 3TB HDD only? Or use the SDD to boot ProxMox?

I would use the SSD with LVM thin for proxmox + storage for your VMs/LXCs and create a zfs mirror with those two 3TB HDDs for SMB usage.
And it would be a good idea to spend 30$ on a second 240GB SSD so you could mirror them too. Not that expensive and if one of the SSDs dies you don't need to setup everything again and you won't loose any data. And with a mirror ZFS could detect errors and repair your files.

 

[oguime]

Doesn't seem a bad starting point, could do with a few more cores or hyperthreading but it is what you have. You could reserve a small partition on the SSD for cache if you like but I don't think you'll see a great benefit in this kind of setup. Personally, I haven't seen any problems with SSD wear-out and if it's just for light duties you will probably be OK.

I suspect your SQL use will be light duties also, so again your use case may not be an issue, but it does pay to be aware of any potential issues.

Your main problem is maybe HomeAssistant as the recommendation seems to be to run it under docker. So you'd have to setup docker on Proxmox first.

Install Samba on the proxmox host for SMB shares and the Unifi controller runs fine as a container.

Hi bobmc,

I'll use the SSD as Dunuin just recommended. Good to know it could work fine for light duties.

And there is a qcow2 HomeAssistant image available. Might try that as well.

Thanks!

 

[oguime]

I would use the SSD with LVM thin for proxmox + storage for your VMs/LXCs and create a zfs mirror with those two 3TB HDDs for SMB usage.
And it would be a good idea to spend 30$ on a second 240GB SSD so you could mirror them too. Not that expensive and if one of the SSDs dies you don't need to setup everything again and you won't loose any data. And with a mirror ZFS could detect errors and repair your files.

Hi Dunuin,

Sounds like a good plan, thanks!

 

[bobmc]

And there is a qcow2 HomeAssistant image available. Might try that as well.

Just seems overkill to spin up a whole VM for something that will run natively on a Raspberry Pi - someone should do an LXC template