Make ISCSI usage simpler

J

JambaFun

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Dec 22, 2014
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Hi!

I am running Proxmox with ISCSI storage in a semi-test setup. Nothing fancy at all, but I'm having a lot of fun with it!

There is one very basic question that I've failed to find an answer to: When is it safe to run multiple VM disks on a single ISCSI target?

Since I don't know this I keep adding new ISCSI targets for every VM disk which is a bit of a hassle to say the least. Not to mention how cluttered the tree becomes. My VMs run nothing but ext2/3/4 and NTFS so far.

What I would like to do is create one giant 1TB ISCSI target in FreeNAS and one giant 1TB LVM accessible by all Proxmox nodes on top of that. Then adding disks to VMs would be a simple one click operation every time, just like local or NFS storage. But would that completely crap up my data?


Best regards
 
Hi spirit!

Yes, doing the whole process according to the wiki works like a charm!

My questions was rather, once I have my LVM on top of my ISCSI storage, is it safe to add multiple VM disks inside that LVM? Or would I risk running into data corruption like you would when connecting multiple initiators to one target in an unsafe manner.

I dislike having to go through 20+ steps everytime a VM needs a new ISCSI backed disk, so I figured I must be doing something wrong.
 
JambaFun said:
Hi spirit!

Yes, doing the whole process according to the wiki works like a charm!

My questions was rather, once I have my LVM on top of my ISCSI storage, is it safe to add multiple VM disks inside that LVM? Or would I risk running into data corruption like you would when connecting multiple initiators to one target in an unsafe manner.

I dislike having to go through 20+ steps everytime a VM needs a new ISCSI backed disk, so I figured I must be doing something wrong.
Click to expand...


No problem, proxmox will create 1 LV by vm disk, and manage lvm across the cluster safely, so you share use 1 target across your whole cluster.
 
How awesome! This means I no longer have to fiddle with multiple ISCSI targets. Thanks for the help.

Wouldn't it be a good idea to add this piece of information to the Wiki page you linked above? Everywhere you read about ISCSI they warn you about sharing an ISCSI target, but with Proxmox that is completely acceptable, and maybe even best practice?
 
JambaFun said:
My questions was rather, once I have my LVM on top of my ISCSI storage, is it safe to add multiple VM disks inside that LVM? Or would I risk running into data corruption like you would when connecting multiple initiators to one target in an unsafe manner.
Click to expand...

there i sno risk of corruption or other mess in the LVM or ISCSI. I safely run all my vm from the same SCSI target, even if I used more sometimes. It is just matter of preferences and flexibility, if you get what I mean. But you are surely safe with one big target, if your ISCSI provider (probably a NAS) works well.

Marco
 
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I suspect that even if one had a TrueNAS system that qualified for enterprise support, they (TrueNAS) would still not provide any help with 3rd party plugin for an external application (PVE). Nor would PVE enterprise support warranty the plugin/storage.
If one was building a production system that required enterprise support, they would need to consider all components : Compute, Storage and Network.

For example, as a storage provider we also created the PVE plugin and warranty both for full compatibility, functionality and performance. We also provide tuning and support of the Proxmox for our customers.

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
 
Is there a solution of ZFS-over-iSCSI that does have enterprise support? I just use Debian which works out-of-the-box, yet I don't need enterprise support because I am the enterprise support ;)
 
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LnxBil said:
TrueNAS Core has no enterprise support, so it does not matter.
Click to expand...
Management is expecting them to help out, and Truenas/ixsystems support seems to have no problem with LVM over iSCSI, they suggested that. I'd be happier with ZFS over iSCSI but that'd mean patching all nodes. And me being the only rocket surgeon in town.
 
tuxick said:
Management is expecting them to help out, and Truenas/ixsystems support seems to have no problem with LVM over iSCSI, they suggested that.
Click to expand...
There is really nothing for them to support, what you do with the iSCSI LUN they present - is your business, whether its LVM, NTFS or VMFS. As long as they exported the iSCSI, their job is complete.

tuxick said:
I'd be happier with ZFS over iSCSI but that'd mean patching all nodes. And me being the only rocket surgeon in town.
Click to expand...
You are exactly right, you'd be taking on both the potential PVE patching on every upgrade, as well as maintaining the driver for, however unlikely, CLI changes on TrueNAS side due to the plugin using command line tools in leu of more stable API.

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
 
bbgeek17 said:
You are exactly right, you'd be taking on both the potential PVE patching on every upgrade, as well as maintaining the driver for, however unlikely, CLI changes on TrueNAS side due to the plugin using command line tools in leu of more stable API.
Click to expand...
Didn't we have an API on the PVE for this for a few years or what was that precisely? Never looked at it ...
 
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