Set up the iSCSI targets list for each adapter.Īdd here only iSCSI adapters IP addresses. Setting up ESXi host and connecting RDM disk to VMsįor target connection, you need to connect software iSCSI adapters on both nodes: Once over with target creation and synchronization, select the device from the console just to doublecheck that everything is set alright. Look one more time at the interconnection diagram: ![]() Next, select the network interfaces you are going to use for Sync and Heartbeat connections. Now, specify the L2 Flash Cache size for the partner node. Select Heartbeat as the failover strategy: On each node, I use 10 GB of SSD space for L2 caching.Ĭreate a StarWind virtual device and select Synchronous “Two-Way” Replication as the replication mode: Well, I have SSD disks in my setup, so I’d like to configure L2 flash cache. I use 1 GB Write-Back cache.Īfterward, specify Flash Cache parameters. Now, that’s time to come up with RAM cache parameters. As I decided to create a thick-provisioned device, I ticked the self-titled radio: Right after StarWind Virtual SAN installation, I created a 100GB Virtual Disk: You should better follow the original guide if you also choose StarWind VSAN. To make the long story short, I highlight only the key points of the installation procedure. StarWind VSAN was installed according to the guide provided by StarWind Software: Now, let’s roll! Installing and configuring StarWind VSAN Important things and step sequence are highlighted in red. Set up ESXi hosts and connect the RDM disk to the VM.Install and configure StarWind Virtual SAN target.Build the test environment and set it up.One more time, today, I’m going to create an RDM-P disk. Note that both hosts have just the same configuration: Now, look at ESXi hosts network configurations. Let’s take a look at ESXi datastore configuration. Find its configuration below:įind the configuration scheme of the setup below: Well, that should be enough if you just want to give the solution a shot. Under the trial license, you are provided with completely unrestricted access to all StarWind Virtual SAN features for 30 days. You can get StarWind Virtual SAN Trial version here: Hosts are orchestrated with VMware vSphere 6.0 (build 8307201).Īs a shared storage provider, today, I use StarWind Virtual SAN (version R6U2). Look, if you are unsure which compatibility mode to pick, check out this article:įor this guide, I use a two-node VMware ESXi 6.5.0 (build 8294253) setup of the following configuration: Still, you can just disconnect RDM from one VM and connect it to another VM or physical server. However, there’re some things about this RDM compatibility mode: VMs with such disks can’t be cloned, migrated, or made into a template. That actually is the mode allowing the guest operating system to talk to the hardware directly. So, the thing I gonna talk about today is RDM-P. Really, there are not that many benefits of using it. It behaves just as if it were a virtual disk, so I won’t talk about it today. Well, RDM-V disk is very close to what VMFS actually is. The former delivers the light SCSI virtualization of the mapped device while the later entirely virtualizes the mapped device and is transparent for the guest operating system. RDMs can be configured in two different modes: physical compatibility mode (RDM-P) and virtual compatibility mode (RDM-V). Well, RDM does not deliver you higher performance than a traditional VMFS, but it offloads CPU a bit. RDM merges some advantages of VMFS with direct access to the physical device. It keeps metadata for managing and redirecting disk access to the physical device. An RDM itself is a mapping file in a separate VMFS volume that acts as a proxy for raw physical storage. Raw device mapping (RDM) provides VMs with the direct access to the LUN. Let’s start with the basics: what RDM is and why to use it Well, apparently, this case is not unique, so I decided to share my experience in today’s article. Recently, I created vSphere VMs with such disks. To enable your VMs to talk directly to LUN, you need a raw device mapping file. Also, with direct access, physical-to-virtual conversion becomes possible without migrating a massive LUN to VMDK. Direct access comes in handy when you, let’s say, run SAN/NAS-aware applications on vSphere VMs, or if you’re going to deploy some hardware-specific SCSI commands. Sometimes, you need your VMs to access a LUN directly over iSCSI.
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