I've got another post open where I'm discussing how to setup a new server that will have a total of 36 available disks and get all VMS to be able to access the data within the single large pool. That post is HERE, in that post, @Dunuin threw me a curve ball and suggested dRaid might be the best way for me to go. If you're not interested in the why of all of this, skip to the end of the post for the dRaid questions.
So off I go to do my homework on dRaid, there really isn't a huge amount of info about it, at least not more easy to understand stuff vs the white paper sort of versions. That said, I think I now understand it but I'd like confirmation that I'm getting it right from people who quite simply have better knowledge on the subject than me, yes that's some of you reading this!
To give a little system detail, the server will have ample ram and CPU power if anything about the raid needs this. The disk availability in the system is as follows:
Here's what I've got to build my new Proxmox server.
System Disks
2 x 4TB SAS in mirror raid as boot disk.
4 x 500gb NVME stripped / mirrored as VM storage.
Storage Disks, I have two possibilities here:
V1
24 4TB SAS disks
5 14TB SATA Disks
5 12TB SATA Disks
V2
22 4TB SAS disks
6 14TB SATA Disks
6 12TB SATA Disks
V2 would require I bought an extra 12tb and 14tb to balance things out a bit.
I'm trying to work out the best way that I can get all of these disks as one large pool.
My original plan was 2 vdevs of Raidz2 with 12 4tb, 1 vdev of raidz1 with the 5 14tb and then finally 1 vdev of Raidz1 withe the 5 12tb.
It was then pointed out to me that having z1 and z2 vdevs in the same pool was a bad idea. so I coud possibly make the total disks balance a bit better as
Storage Disks
22 4TB SAS disks
6 14TB SATA Disks
6 12TB SATA Disks
Making 2 vdevs of Raidz2 with 12 4tb, 1 videv of raidz2 with the 6 14tb and then finally 1 vdev of Raidz2 withe the 6 12tb.
That was the original plan, enter Dunuin with the dRaid curve ball......
To my understanding, I can still create multiple dRaid vdevs and add them to a pool in Proxmox, I've done some experimenting and it works the same as raidz vdevs in to a pool from command line.
Here's where I need help understanding the mechanics of dRaid.
I will mostly be storing large backups archives and generally large files. The system can be accessed by up to 6 users at the same time.
With the 4TB drives, would dRaid2:10d:2s:22c create essentially the same as having 2 x 10 disks raidz2 withe the addition of 2 hot spares? Or will it only have 2 parity disks for the whole 22 disk array? What type of vDevs would I then be better using for the 14tb and 12tb disks?
Further on from that, if I did dRaid2:1d:2s:22c on the 4TB disks, would this essentially create 20 1 disk arrays to stripe across when writing? Is this actually better or worse for space / disk speed as I read that no matter what the file size, dRaid will complete a stripe with zeros if there isn't enough data to actually fill it up.
To add to the to what I see as the complexity of my decision, I could add further 500gb nvme SSD to the system as special devices, though I'm not quite sure how I include those and weather they'd be a good / worthwhile addition?
So it's over to you with the increased knowledge and understanding, hopefully you can explain to me what likely to work well.
So off I go to do my homework on dRaid, there really isn't a huge amount of info about it, at least not more easy to understand stuff vs the white paper sort of versions. That said, I think I now understand it but I'd like confirmation that I'm getting it right from people who quite simply have better knowledge on the subject than me, yes that's some of you reading this!
To give a little system detail, the server will have ample ram and CPU power if anything about the raid needs this. The disk availability in the system is as follows:
Here's what I've got to build my new Proxmox server.
System Disks
2 x 4TB SAS in mirror raid as boot disk.
4 x 500gb NVME stripped / mirrored as VM storage.
Storage Disks, I have two possibilities here:
V1
24 4TB SAS disks
5 14TB SATA Disks
5 12TB SATA Disks
V2
22 4TB SAS disks
6 14TB SATA Disks
6 12TB SATA Disks
V2 would require I bought an extra 12tb and 14tb to balance things out a bit.
I'm trying to work out the best way that I can get all of these disks as one large pool.
My original plan was 2 vdevs of Raidz2 with 12 4tb, 1 vdev of raidz1 with the 5 14tb and then finally 1 vdev of Raidz1 withe the 5 12tb.
It was then pointed out to me that having z1 and z2 vdevs in the same pool was a bad idea. so I coud possibly make the total disks balance a bit better as
Storage Disks
22 4TB SAS disks
6 14TB SATA Disks
6 12TB SATA Disks
Making 2 vdevs of Raidz2 with 12 4tb, 1 videv of raidz2 with the 6 14tb and then finally 1 vdev of Raidz2 withe the 6 12tb.
That was the original plan, enter Dunuin with the dRaid curve ball......
To my understanding, I can still create multiple dRaid vdevs and add them to a pool in Proxmox, I've done some experimenting and it works the same as raidz vdevs in to a pool from command line.
Here's where I need help understanding the mechanics of dRaid.
I will mostly be storing large backups archives and generally large files. The system can be accessed by up to 6 users at the same time.
With the 4TB drives, would dRaid2:10d:2s:22c create essentially the same as having 2 x 10 disks raidz2 withe the addition of 2 hot spares? Or will it only have 2 parity disks for the whole 22 disk array? What type of vDevs would I then be better using for the 14tb and 12tb disks?
Further on from that, if I did dRaid2:1d:2s:22c on the 4TB disks, would this essentially create 20 1 disk arrays to stripe across when writing? Is this actually better or worse for space / disk speed as I read that no matter what the file size, dRaid will complete a stripe with zeros if there isn't enough data to actually fill it up.
To add to the to what I see as the complexity of my decision, I could add further 500gb nvme SSD to the system as special devices, though I'm not quite sure how I include those and weather they'd be a good / worthwhile addition?
So it's over to you with the increased knowledge and understanding, hopefully you can explain to me what likely to work well.