western digital SE vs. RE
What is the difference between the two? I'm about to get either wd hdd RE or SE w/250 gbs and can't figure out which one is best for me.
not positive which hdds you wondering about specifically, but here are 2 western digital links that fit what youre asking, so you can compare the differences
WD Caviar SE 250 GB SATA Hard Drives ( WD2500JS )
WD RE 250 GB SATA Hard Drives ( WD2500YS )
Right, that's the ones. Earlier, I was at that site and still couldn't figure out why the RE is not listed with the "desktop memory" selections. There are a variety of SE's on that page but not one mention of the RE hdd. That kinda threw me. Why is it not listed with the other desktop hdd's on WD's site?
I'm going to start with just one hdd but plan on expanding up to my mobos limits in the near future. I thought to employ RAID you had to have all identical drives. Is that not correct? That is why I'm trying to figure out which one I should start with. Technically, I wouldn't be using RAID until I purchase some more drives. I'm putting together a new rig and can afford only one drive at the moment. Which one should I get?
The RE is the high reliability version and has a 5-year warranty that the SE does not. The RE has a bigger cache 16 MB vs 8 MB and a faster track to track seek time 0.6 vs 2.0. Both will work in RAID configurations. The RE will cost a bit more.
Edit: RAID configurations can be built with mixed drives (both sizes and types) but the most straight forward is matched drives.
its not in the desktop section because its considered an enterprise drive
from WD themselves:Quote:Q: Regular 7200 RPM desktop drives run fine in RAID environments; why do I need these drives? A: Unlike regular desktop drives, WD RE SATA and EIDE hard drives are engineered and manufactured to enterprise-class standards and include features such as time-limited error recovery that make them an ideal solution for RAID.
Q: What is time-limited error recovery and why do I need it?
A: Desktop drives are designed to protect and recover data, at times pausing for as much as a few minutes to make sure that data is recovered. Inside a RAID system, where the RAID controller handles error recovery, the drive needn't pause for extended periods to recover data. In fact, heroic error recovery attempts can cause a RAID system to drop a drive out of the array. WD RE2 is engineered to prevent hard drive error recovery fallout by limiting the drive's error recovery time. With error recovery factory set to seven seconds, the drive has time to attempt a recovery, allow the RAID controller to log the error, and still stay online.
Q: Will these drives work with my existing power supply?
A: The WD RE SATA drive has the new 15-pin SATA power as well as the legacy 4-pin power connectors. (Do not connect both connectors at the same time.) The WD RE EIDE drives use the industry-standard 4-pin power connector.
Q: What about SATA connections? Is the drive hot pluggable?
A: The WD RE SATA works with latching SATA cables, non-latching SATA cables and SecureConnect™. SecureConnect is available only for WD SATA drives and provides additional structural support where the SATA cable connects to the hard drive. The WD RE drive is compatible with SATA backplanes and SATA hard drive carriers and, in those environments, is hot pluggable.
Q: For RAID environments I need SCSI data integrity.
A: The Serial ATA version includes 32-bit CRC error checking for all bits transmitted: command, data, and status. And, both SATA and EIDE versions include error checking to compare the data read back from the hard drive tob the data originally written to the hard drive.
IME, the enterprise drives are slightly louder. they seem to have been designed with a server room in mind, rather than a small home office.
edit: they DO sell SE versions with 16 mb cache, so dont let that be the deciding factor.
This is the WD position from their siteQuote:Question
What is the difference between Desktop edition and RAID (Enterprise) edition hard drives?
Western Digital manufactures desktop edition hard drives and RAID Edition hard drives. Each type of hard drive is designed to work specifically in either a desktop computer environment or on RAID controller.
If you install and use a desktop edition hard drive connected to a RAID controller, the drive may not work correctly. This is caused by the normal error recovery procedure that a desktop edition hard drive uses.
When an error is found on a desktop edition hard drive, the drive will enter into a deep recovery cycle to attempt to repair the error, recover the data from the problematic area, and then reallocate a dedicated area to replace the problematic area. This process can take up to 2 minutes depending on the severity of the issue. Most RAID controllers allow a very short amount of time for a hard drive to recover from an error. If a hard drive takes too long to complete this process, the drive will be dropped from the RAID array. Most RAID controllers allow from 7 to 15 seconds for error recovery before dropping a hard drive from an array. Western Digital does not recommend installing desktop edition hard drives in an enterprise environment (on a RAID controller).
Western Digital RAID edition hard drives have a feature called TLER (Time Limited Error Recovery) which stops the hard drive from entering into a deep recovery cycle. The hard drive will only spend 7 seconds to attempt to recover. This means that the hard drive will not be dropped from a RAID array.
If you install a RAID edition hard drive in a desktop computer, the computer system may report more errors than a normal desktop hard drive (due to the TLER feature). Western Digital does not recommend installing RAID edition hard drives into a desktop computer environment.
The Time Limited Error Recovery changes the behavior of the drive when it is involked (the disk has errors and is trying to recover). It is not an issue under normal conditions. As you can see from the WD site both drives can be stand alone or in a RAID configuration with the above noted performance difference.