Reality Check: Server Insights : hard drive

Will 6Gb/s SAS make a difference for you?

s_mathur — Mon, 13 Jul 2009 03:17:00 GMT

Some of you read my post on drive performance, 'How fast are your drives?,' and have wondered if investing in a 6Gb/s SAS storage infrastructure makes sense for your environment. Traditional SAS systems have a transfer rate of 3Gb/s, so the new HP 6Gb/s SAS drives and Smart Array controllers have doubled the available bandwidth of storage subsystems.

Given that 6Gb/s refers to the system throughput or the speed at which data travels among the components of the storage subsystem (the drive, controller, server backplane, and/or SAS expander and JBOD), will your system performance really improve? Well, if your environment consists of a small number of storage devices and your I/O workload is 40% or less, you probably won't see any benefits beyond generational improvements (e.g. performance and technology improvements that happen over time). In such environments, the bottleneck may actually be the speed at which bits can be moved to (from) the hard disk platters from (to) the hard disk's integrated controller and the fast transfer among storage devices may be "wasted."

However, if you're running multi-device, storage-intensive applications, such as video streaming, server virtualization, or real-time backup systems, you'll want to make sure your system doesn't saturate as often and pumping data through the system faster will help keep up with your heavy I/O demands.

If you're running a ProLiant G6 server and have a 6Gb/s SAS storage infrastructure, let's hear what kind of application you're running.

The drives matter: HP G6 server benchmarks

s_mathur — Sun, 31 May 2009 02:31:00 GMT

Have a high performance environment? Are you trying to create a green data center. The drives matter! Choosing a drive isn't all about capacity.

In his blog "For HP servers, what a difference a drive makes!", Pete Steege comments on the HP DL370 G6 and HP DL380 G6 benchmarks and how the choice of drives can affect system metrics.

Click here to read Pete's blog.

Business data continues to grow

s_mathur — Fri, 29 May 2009 15:15:00 GMT

Many customers are seeing IT spending cuts nowadays, but business hasn't stopped even if it isn't growing. Your company may have slowed down on purchasing computer hardware, but for most HP customers, storage needs have continued to grow despite the economic downturn. Jimmy Daley, manager of the Server Options Marketing Team at Hewlett-Packard talks about this growth trend in an interview with Pete Steege from Seagate Technology. In this interview, Jimmy talks about

Virtualization as a driver for increased storage capacity
Increased drive count per server
Customers segmenting their data storage needs between performance and bulk storage
HP's move towards blade servers and how 2.5inch drives are a key component for space consolidation and power reduction efforts.

See the interview posted on YouTube: http://www.youtube.com/watch?v=HUSMbCdBvRA.

Why HP Drives? The proof is in the pudding...

s_mathur — Thu, 07 May 2009 19:56:00 GMT

By Stephanie Whalen. At HP we believe business success is all about your data. One of the most important investments you can make is in your drives. A common question we get is "isn't your drive the same as what I can buy through a retail chain?" The answer is a resounding NO.

There are several differences and reasons why HP drives are the best choice for your HP ProLiant, Integrity and StorageWorks platforms. First and foremost is the rigorous HP qualification process known as the Hard Disk Drive Qualification (HDDQ) system. HDDQ covers a multitude of design aspects, such as, drop tests, random vibration, temperature testing, signal integrity, power, performance, rotational vibration and the list goes on and on. If the drive doesn't pass any part of the test, corrective measures are taken to fix anything out of spec before the drive is released to production - OR the drive gets the boot. By the time all required testing is completed, HP drives have endured in excess of 2 million drive test hours. Second, HP and our drive suppliers walk hand-in-hand throughout this process to ensure the best possible drive is delivered to our customers. We continue to do so even after the drive is in full production. It is through the HP Hard Disk Drive (HDD) closed-loop quality system where we and the drive suppliers ensure all quality metric goals are achieved and continues to do so throughout the lifecycle of the product.

Our drives have been tested to ensure compatibility and optimized to work with our servers and storage enclosures. Through the combination of server chassis design, qualification testing, HP drive firmware, and drive technology, HP drives provide better performance, less downtime and increased data integrity than third-party drives. Without proper engineering, drive performance can suffer from 25% to 50% due to vibration and retries, however with the right chassis design and drive trays and correct type of drives, HP drives operate at optimal performance level.

The proof is in the pudding. Based on vendor statistics our HP drives for enterprise applications have up to 50% less return rate compared to drives sold in the retail space.

Makes you wonder what you get when you buy off the shelf.

For more info, see www.hp.com/products/harddiskdrives or the whitepaper HPHDD Quality System – The Driving Force of Reliability at http://h18004.www1.hp.com/products/servers/proliantstorage/drives-enclosures/docs/index.html.

2.5-inch Drives vs. 3.5-inch Drives

s_mathur — Tue, 28 Apr 2009 20:41:00 GMT

While the majority of the internal and external systems use 3.5-inch drives, HP has lead the path to 2.5-inch drives through its server and storage offerings. Some would argue that the lower cost per GB is the reason why the 3.5-inch drives have remained so popular; others would point to the capacity gap - 2.5-inch drives offer about half the capacity of 3.5-inch drives. However, there's a growing number of people who have realized the energy costs need to be considered as well as the acquisition cost per GB.

IDC discusses the capacity gap, the cost to power and cool storage, as well as the industry transition to 2.5-inch drives in a whitepaper available at: http://h18004.www1.hp.com/products/servers/proliantstorage/drives-enclosures/docs/216652_IDC_Paper_2009FEB20.pdf.

In the paper, IDC states:

The 2.5inch SFF performance-optimized HDD is already well-recognized for providing greater storage density and higher IOPS per U in server and storage systems as well as consuming less power. But a 2.5inch form factor HDD carries a capacity penalty of roughly half that of a similar-generation 3.5inch HDD. The reason is simple: 3.5inch HDDs can have a maximum of four platters per drive, while current performance optimized 2.5inch HDDs have a maximum of two platters per drive. However, this is not a fixed rule, and HDD configurations are about to change.

IDC goes on to predict that "the HDD industry's last generation of 3.5inch performance-optimized HDDs will be launched in 2009."

Do you agree that the server and storage industry will transition to 2.5-inch drives faster than before?

Solid State Develops

s_mathur — Fri, 24 Apr 2009 13:52:00 GMT

By Susan Riley. There seems to be a lot of interest in SSD's lately. With all the different product offerings out there it is hard for the user to fully understand what type of product they need. There is the MLC variety that is high performance, higher capacity but lower endurance based on the number of write cycles and then there is the more expensive, smaller capacity SLC offerings that delivers higher performance and higher endurance levels. What to choose? MLC is typically used in consumer applications while SLC has developed in the enterprise space. The suppliers range in experience from drive suppliers to memory suppliers to smaller start up companies that put components on a PCBA and sell it as solid state. We segment the solutions into 4 categories, those that are externally attached (highest latency), "drive like" solutions, those that install on the PCIe bus and those that fit on the memory bus (lowest latency).

Visit our website to learn more: www.hp.com/go/solidstate.

How fast are your hard drives?

s_mathur — Tue, 21 Apr 2009 03:54:00 GMT

When it comes to choosing hard drives, there are several measures of performance that may influence your decision.

An important parameter for overall drive performance is revolutions per minute (abbreviated rpm, RPM, r/min, or r·min⁻¹); this is the speed at which the disk platters spin. High rpms mean data passes the read/write heads of the drive faster. In general, the higher the rpm of the drive, the faster data is accessed or stored on the platter. Drive vendors normally state the rpms of a drive as part of the name. HP SATA drives currently spin at 5400 or 7200 rpm while HP SAS drives come in 7200, 10,000, or 15,000 rpm speeds.

IOPS (input/output operations per second) is a set of common benchmarks for hard disks measuring the number of:

Sequential read
Sequential write
Random read, or
Random write

I/O operations per second (or a combination of all four). IOPS is normally measured in laboratories and so real life performance can vary greatly depending on the nature of the application and the system architecture as a whole. Note that random IOPS figures depend on the drive’s random seek time, whereas the sequential IOPS numbers are an indicator of the data transfer rate of the drive.

Seek time is the time it takes to move the read/write head to the right place on the platter. Related to seek time is rotational delay or latency: the time required for the addressed area of the disk to rotate to the position where the read/write head can get to it. The transfer time is the time it takes to actually read or write data from/to the platter. All three of these and spin-up time (the time needed to speed the disk to operating speed )determine the disk access time of a drive.

One other common term used when talking about drive performance is data transfer rate. This is often measured in bits per second and refers to the average rate data is moved from the drive to the storage controller. Often when people talk about data transfer rate, they are actually talking about system bandwidth or throughput, which is the rate at which data travels from the drive to other components of the server/system. The throughput of the system depend on the data transfer rates of the drive, the controller, and the system BIOS and chipset – any one of these can be a bottleneck.

So, is rpm the most important measure of drive performance for your application/environment, or do you normally pay more attention to the other measures?