- Drivers Oracle Scsi & Raid Devices Download
- Drivers Oracle Scsi & Raid Devices Usb
- Drivers Oracle Scsi & Raid Devices Configuration
The following examples are for tuning the generic SBP2 interface, but the techniques can also be supplied to specific SCSI drivers. First, let's look at the current settings for the interface. You get those by looking under the LUN number in the /proc/scsi/sbp2 directory. I'm quite confused about Solaris8 device driver support for the Sun dual-channel single-ended ultra-wide PCI SCSI adapter (X6540A). I just recently purchased this SCSI adapter and a reconditioned SUN-XG-XTAP4MM-012A Unipack (which actually contains an HP C5683A SureStore DAT40 DDS4 tape drive). Primarily for compatibility with other virtualization software, Oracle VM VirtualBox optionally supports LSI Logic and BusLogic SCSI controllers, to each of which up to fifteen virtual hard disks can be attached.
IDE (ATA) – this was the most widely used controller standard, but it has certain limitations and is now being replaced by the SATA standard. These controllers are backward compatible. So, if a guest operating system doesn’t support SCSI or SATA, it would fall back to use IDE (ATA). For each guest VM in VirtualBox, there might be one IDE controller enabled that supports or allows up to four storage devices to be connected to a guest VM. It does so by using the primary master, secondary master, primary slave, and secondary slave slots. Out of these four storage devices, the secondary device master slot is preconfigured for CD/DVD devices. If additional IDE disks are required, the VirtualBox SATA controller for the VM must be enabled in the SATA IDE compatibility mode. If you migrate a guest VM from another virtualization solution to VirtualBox, then you are expected to provide the exact controller type. In VirtualBox, you can select the PIIX3, PIIX4, or ICH6 controller type.
Serial ATA (SATA) – the most widely used and latest drive controller standard. Compared to IDE, SATA provides both much higher speeds and more devices per controller. Also, with physical hardware, devices can be added and removed while the system is running. The standard interface for SATA controllers is called Advanced Host Controller Interface (AHCI). Like a real SATA controller, VirtualBox’s virtual SATA controller operates faster and also consumes fewer CPU resources than the virtual IDE controller. Also, this allows you to connect up to 30 virtual hard disks to one machine instead of just three, as with the VirtualBox IDE controller (with the DVD drive already attached). VirtualBox uses SATA as the default for newly created virtual machines. One virtual SATA controller is created by default, and the default disk that is created with a new VM is attached to this controller.
Small Computer System Interface (SCSI) – this is now a popular storage connection standard. Today SCSI is still used for connecting hard disks and tape devices, but it has mostly been displaced in commodity hardware .This standard is based on a bus topology allowing up to 15 storage devices to be connected to a disk controller in a daisy chain configuration. Each of the devices is assigned a unique SCSI identifier, which distinguishes the devices from each other on the SCSI bus. VirtualBox provides emulation for BusLogic and LSI Logic SCSI disk controllers.
Serial Attached SCSI (SAS) – another bus standard which uses the SCSI command set. As opposed to SCSI, however, with physical devices, serial cables are used instead of parallel ones, which simplifies physical device connections. In some ways, therefore, SAS is to SCSI what SATA is to IDE: it allows for more reliable and faster connections. To support high-end guests which require SAS controllers, VirtualBox emulates a LSI Logic SAS controller, which can be enabled much the same way as a SCSI controller. At this time, up to eight devices can be connected to the SAS controller.
Oracle VirtualBox course
I wrote a blog article in Oct 2010 on this same topic that is still frequently referenced today so I figure it was due for an update.
So what should I choose as my vSCSI controller and what are the differences between them?
First, it’s important to remind everyone that when you select the Guest OS for a new virtual machine
this automatically makes a selection for which vSCSI controller to use based on what drivers are available in the OS distribution. So be sure to select the correct Guest OS to start in the right place.
Let’s look at the options available today:
- BusLogic – this was one of the first emulated vSCSI controllers available in the VMware platform. The earliest versions of Windows has this driver available by default which made it easy when installing that particular OS. It wasn’t however as performant as the LSI Logic driver since Windows’ driver was limited to a queue depth of 1, so often one would manually load the LSI Logic driver instead. While still available and used occasionally (Is anyone still running Win2K?), it should be considered legacy.
- LSI Logic Parallel (formerly knows as just LSI Logic) – this was the other emulated vSCSI controller available originally in the VMware platform. Most operating systems had a driver that supported a queue depth of 32 and it became a very common choice, if not the default.
- LSI Logic SAS – This is an evolution of the parallel driver to support a new future facing standard. It began to grown popularity when Microsoft required its use for MCSC within Windows 2008 or newer.
- VMware Paravirtual (aka PVSCSI) – this vSCSI controller is virtualization aware and was been designed to support very high throughput with minimal processing cost and is therefore the most efficient driver. In the past, there were issues if it was used with virtual machines that didn’t do a lot of IOPS, but that was resolved in vSphere 4.1.
Are there performance differences between them?
- PVSCSI and LSI Logic Parallel/SAS are essentially the same when it comes to overall performance capability. PVSCSI, however, is more efficient in the number of host compute cycles that are required to process the same number of IOPS. This means that if you have a very storage IO intensive virtual machine, this is the controller to choose to ensure you save as many cpu cycles as possible that can then be used by the application or host. Most modern operating systems that can drive high IO support one of these two controllers.
- Here’s a detailed whitepaper that takes a closer look at PVSCSI vs LSI Logic SAS for IOPS, Latency and Cost. While it does support that PVSCSI is more capable, keep in mind most customers are not producing 1 million IOPS so for real life the difference is negligible.
How many vSCSI adapters are supported per virtual machine?
- It’s also worth noting that you can configure a total of 4 vSCSI adapters per virtual machine. To provide the best performance, one should also distribute virtual disk across as many vSCSI adapters as possible. This configuration provides the capability to process more IO simultaneously and benefit from additional queues if necessary.
Drivers Oracle Scsi & Raid Devices Download
What about AHCI SATA?
Drivers Oracle Scsi & Raid Devices Usb
- This is a new storage controller available with vSphere 5.5 and virtual hardware 10. It allows you to connect a large amount of storage to a virtual machine but it wasn’t designed to be as efficient as the PVSCSI or LSI Logic controllers and therefore should not be used with performance sensitive applications.
Drivers Oracle Scsi & Raid Devices Configuration
Let’ summarize this in a chart: