Can I connect multiple consumer servers to the same iSCSI?

Question

network hardware

The hoster gives the iSCSI target of the selected size. And you can connect to it and create disks there. But in the same place in the control panel and in the documentation they write

Warning: The iSCSI LUNs should only be installed on a single server at the same time. Apart from some very specific cases (adapted file system software supporting cluster mode, etc.), mount a LUN across multiple servers simultaneously will result in data corruption.

I have no experience with iSCSI yet. Does this mean that I need to buy iSCSI separately for each server? I thought you can somehow scale the load. For example, two image servers will connect to the same iSCSI storage. Does it mean that it won't work?

Or I read badly, and it says about "very specific and rare" cases. And in a normal connection, everything will work fine?

Answer 1

You can connect. But the file system on a shared volume must be clustered, such file systems are just designed for such use. NTFS, Ext4, etc. unsuitable. For example, VMFS from VMWare is clustered.
If you connect several consumers to an iSCSI partition with a regular FS, then the FS will fall fairly quickly.

Answer 2

It is possible - and this is how, for example, shared storage is implemented for the Proxmox virtualization system.
But, as your manual says quite correctly, it is impossible for the same objects to be touched from several places at once - and this is not only for iSCSI. Usually this is decided at the application level - somehow (for example, over the network) access is coordinated.
In read-only mode, this is easier - you cannot corrupt the data if you do not make any changes to it. If the pictures for your storage will be recorded from one point, there should be no problems.

Answer 3

You are confusing warm with soft. iSCSI is a block disk access protocol. LUN is a way to organize storage. iSCSI can have multiple initiators and targets. Only one host should write to the LUN - the LUN does not know anything about hosts at all, it will write everything that comes without parsing where it is and the result is not predictable.
In general, you were warned that you yourself must ensure that only one host writes to the LUN, otherwise data corruption is possible, several can read.
You were given a management console from the storage system. Or rather, a piece of it. If you can create LUNs there yourself and associate them with hosts, then what you want is done without problems. Create moons of the required size in your disk pool and assign them to your servers, mount these moons in the servers, create a file system and use it.