Dell 36.7GB SCSI Hard Drive for PowerEdge Review

Bottom-line: If you need a reliable, high performance SCSI hard drive for your new or excising Dell server, look no further then the 3.5" Dell 36.7GB hard drive.  

Many people have asked me why-if the newest generation of ATA hard drives hold so much more information (in some cases as much as 50% more data, though Seagate has introduced a 300GB SCSI drive)-don't servers utilize those drives instead of the much more expensive SCSI drives.  The short answer is seek time, measured in milliseconds (ms); i.e. the time it takes for the hard drive to access information and relay it to the requester.  This directly translates to throughput.    

The newer Serial ATA (SATA) drives have managed to get seek time down to 8.5ms while the average seek time for an Ultra SCSI drive is 4.0ms.  Seek time in turn is tied directly to the hard drive spindle rotation rate or how fast the platters which, holds the data, spins (measured in RPM) within the hard drive housing.  Top end SATA drives and traditional Parallel ATA (PATA) drives are rated at 7200 RPM, though some Seagate drives are rated as high as 7200.7 RPM, while most SCSI drives installed in serves today are rated at either 10,000 or 15,000 RPM.  The faster the platters spins the lower the seek time, which leads to quicker delivery of information, and faster overall performance.      

Add to this mix the fact that all SCSI hard drives can be "Hot Swapped," which is the ability to remove the drive from the server while the later is powered on and operating.  This is very important when you cannot afford for a file or application server to experience downtime in the middle of the production day.  No PATA drives can make this claim, while some SATA drives again by Seagate do have this capability.  To be sure some SATA drives are now being used in entry-level servers targeted at small businesses. 

The Drive

The business purchases Dell servers exclusively for mid-to-high end file and application functions.  The servers are routinely ordered the server with at least two Dell 36.7GB SCSI hard drives, which are really just re-badged IBM, Maxtor, or Seagate drives.  I install the Operating System (OS) on two of these drive configured to mirror one another.   The drive is incased in a standard 3.5" form factor and will fit the drive sleds of all of the below mentioned servers.

The Dell 36.7GB hard drive is a relatively inexpensive (for SCSI), middle of the road hard drive, which features a Ultra320 SCSI (168-pin) interface, 10,000 or 15,000 RPM speed, a large 8 MB cache, a low 4.7ms seek time, and data transfer rates of up to 320 MBps (Megabyte per second).  The Dell 36.7GB SCSI hard drive supports Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.)-a feature found on many ATA drives-which alerts the system of any negative reliability status conditions. The host SCSI array can then alert and advise the administrator on taking appropriate actions to avoid potential disk failure or downtime.  According to Dell, the Dell 36.7GB SCSI hard drive "has been tested and validated on Dell systems to ensure it will work with your computer and is compatible with Dell PowerEdge Servers 1600 / 1650 / 2600 / 2650 / 4600 / 6600 / 6650 and PowerVault 220 / 221 Systems."

A word, or two, about Ultra320 SCSI

Ultra320 is the latest SCSI iteration, which provides the highest SCSI bandwidth to date: up to 320MBps.  Ultra320 SCSI is the follow-on to Ultra160 SCSI, which as you can surmise provided a bandwidth of up to 160MBps.  Ultra320 SCSI was designed to meet the demand for increasingly robust server applications, such as SQL, DB2, and Oracle databases, Peoplesoft, SAP, etc. 

Not only does Ultra320 double SCSI's peak performance from 160 MBps to 320 MBps, but the newer interface also includes innovations that increase data protection and optimize performance; e.g. multiple file transfers are realized through a single host-target connection via improvements in packet protocol.  The latest iteration of SCSI doubles the drive capacity of the array to 14 devices, be they hard drives, tape backup units, or some other SCSI device.  This is a capability IDE /SATA technology just can't match.     

My Viewpoint

I do not routinely test the actual throughput of the drives installed in my servers, because there really is no need, or time to do so.  But you monitor performance via Windows 2xxx built-in Performance Monitor tool.  Sufficed to say that I am very please with their overall performance.  In the three years I have been working with these drives I have yet to experience downtime due to malfunction and my servers are up 24/7/365.  I usually install up to two 36.7GB drives in a server and institute RAID Level 1 (mirrored configuration, when one drive emulates another) across the array and then install the Operating System (OS) on the resulting mirrored container.    

If you need a reliable, high performance SCSI hard drive for your new or excising Dell server, look no further then the 3.5" Dell 36.7GB hard drive. 

Technical Features

• Interface Type: SCSI Ultra 160/320
• External Data Transfer Rate: 160/320 MBps
• Seek Time: 4.7 ms
• Buffer Size: 8MB
• Average Latency: 2 ms
• Capacity (Raw): 36.7GB
• Capacity (Formatted NTFS): 34.0 GB
• Spindle Speed: 10,000 / 15,000 RPM
• Drive Dimensions: 3.5" x 1/3H
• Enclosure: Internal