- May 14, 2014
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i see WD do green and black etc but nomention of red.whats the difference and where does it fit in the array?
- Thread starter pimpanther
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jimmysmitty
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- Oct 5, 2007
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WD Drives:
WD Green: Low end 5400RPM drive, can be a bit faster but cheapest of them all
WD Blue: Mid level 7200RPM HDD. Good for basic builds
WD Black: Best consumer HDD, 7200 RPM with high performance and great warranty
WD Red: High end NAS consumer drive, designed for 24/7 operation and high write/read operations
Pretty much only get a WD Red if you want a server/NAS HDD. Any other time you get a WD Black or a Seagate.
WD Green: Low end 5400RPM drive, can be a bit faster but cheapest of them all
WD Blue: Mid level 7200RPM HDD. Good for basic builds
WD Black: Best consumer HDD, 7200 RPM with high performance and great warranty
WD Red: High end NAS consumer drive, designed for 24/7 operation and high write/read operations
Pretty much only get a WD Red if you want a server/NAS HDD. Any other time you get a WD Black or a Seagate.
- May 27, 2010
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Black: Speed and Warranty 5 year
Blue: Speed less Warranty 2 year
Red: Intended for RAID in consumer products
Purple: DVR and Security (Many overwrites)
Green: Energy savings and capacity
SE: Entry level SAS Enterprise
RE: High end SAS Enterprise
Blue: Speed less Warranty 2 year
Red: Intended for RAID in consumer products
Purple: DVR and Security (Many overwrites)
Green: Energy savings and capacity
SE: Entry level SAS Enterprise
RE: High end SAS Enterprise
Solandri
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- Jan 4, 2012
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Note that some (most?) WD Green drives have an inordinately short head parking timer baked into the firmware. The drive will park the heads after something like 6 seconds to save power. A lot of people worry this will reduce the life of the part. WD says it won't, but there are firmware hacks out there to make it behave more like a normal drive, and park the heads only when spinning down the drive.
WD Black = WD Blue with a longer warranty.
WD Red has something called TLER, which helps prevent drives from dropping out of a RAID array due to a simple read error. When a single drive encounters a read error, it repeatedly re-reads the sector trying to get a clean read (i.e. the checksum matches the data that was read). These re-read attempts can frequently last over a minute before the drive gives up and the OS reports a read error.
Most RAID software will consider the drive to have failed if it doesn't report back from a read request in as little as 6 seconds. So if a drive gets stuck trying to re-read a sector like this, the RAID software may mistake it for a failed drive and drop it from the array. To counter this, the RAID software changes a setting on the drive which makes it give up re-reading in less than 6 seconds. On WD drives, this setting is called TLER. It's present on the WD Red drives, but not the others.
Note that WD is the only HDD company which specifically disabled TLER in its other drives to create a "NAS drive" category. With the other manufacturers, all their drives have an equivalent setting and will work with RAID arrays. And newer RAID software knows about WD's hanky-panky and can be configured to or will not automatically drop a drive if it takes a long time with a read request.
WD Purple are for security cameras. I haven't figured out what features (supposedly) make these drives better for security cameras.
WD Black = WD Blue with a longer warranty.
WD Red has something called TLER, which helps prevent drives from dropping out of a RAID array due to a simple read error. When a single drive encounters a read error, it repeatedly re-reads the sector trying to get a clean read (i.e. the checksum matches the data that was read). These re-read attempts can frequently last over a minute before the drive gives up and the OS reports a read error.
Most RAID software will consider the drive to have failed if it doesn't report back from a read request in as little as 6 seconds. So if a drive gets stuck trying to re-read a sector like this, the RAID software may mistake it for a failed drive and drop it from the array. To counter this, the RAID software changes a setting on the drive which makes it give up re-reading in less than 6 seconds. On WD drives, this setting is called TLER. It's present on the WD Red drives, but not the others.
Note that WD is the only HDD company which specifically disabled TLER in its other drives to create a "NAS drive" category. With the other manufacturers, all their drives have an equivalent setting and will work with RAID arrays. And newer RAID software knows about WD's hanky-panky and can be configured to or will not automatically drop a drive if it takes a long time with a read request.
WD Purple are for security cameras. I haven't figured out what features (supposedly) make these drives better for security cameras.
IIRC, The storage medium on the platters is formulated to last through 5-10 times as many write cycles, and is archive-grade (will hold data for 30+ years when disconnected.) Believe it or not, hard drives can degrade from over-writing like SSDs, just not as quickly, and they can slowly demagnetize in storage.
jimmysmitty
Champion
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The platters lose the ability to magnetize and demagnetize over time. But as you said, it takes a lot longer than current SSDs, although the new 3DNAND Intel has might finally put SSDs above HDDs in that too.
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