Drive writes per day

Comparing DWPD to TBW

TBW-DWPDA couple of specifications for SSD endurance are in common use today: Terabytes Written (TBW) and Drive Writes Per Day (DWPD).  Both are different ways to express the same thing.  It seems that one vendor will specify endurance using TBW, while another will specify DWPD.  How do you compare the two?

First, some definitions.  “Terabytes Written” is the total amount of data that can be written into an SSD before it is likely to fail.  “Drive Writes Per Day” tells how many times you can overwrite the entire capacity of the SSD every single day of its usable life without failure during the warranty period.  Since both of these are guaranteed specifications, then your drive is most likely to last a lot longer than the number given by the SSD’s maker.

To convert between the two you must know the disk’s capacity and the warranty period.  If  drive maker gives you TBW but you want to know DWPD you would approach it Continue reading

Seagate’s Big Intro: Four New SSD Families in One Day

Seagate's Four New SSD FamiliesSeagate this week updated its SSD portfolio with four new product families and now claims to have the broadest portfolio of storage products in the industry.  This announcement squarely places the company in all the key SSD markets: SATA, SAS, and PCIe.

Here’s Seagate’s new lineup:

  • Seagate 600 6Gb/s SATA, a drive that Seagate calls: “The ultimate laptop upgrade”.  The company claims that this is the first Continue reading

SMART Optimus Ultra+ SSD: SLC Performance Using MLC Flash

SMART Guardian vs Normal Flash Management - More good BlocksSMART Storage Systems has introduced a new enterprise-class SSD that the company says: “increases the endurance of cMLC Flash to a level that makes SLC drives obsolete.”  That’s a pretty hefty claim!

The new Optimus Ultra+ SSD is specified at 100K read IOPS and 60K write IOPS, through its 6Gb/s SAS interface.  With capacities ranging from 100-800GB, this SSD supports up to 50 full drive writes per day over its 5-year lifespan, double that of the company’s Optimus Ultra which was introduced in February.  That’s quite something for an MLC-based SSD.

SMART has tapped into its Guardian technology to reap SLC benefits from MLC flash through both enhanced external and internal algorithms.  Like all other SSD makers and SSD controller makers SMART has focused a lot of attention on error correction, DSP, and other means of correcting errors externally to the flash.  The company has also partnered with Continue reading

Contact

Jim Handy
Objective Analysis
SSD Market Research
+1 (408) 356-2549
Jim.Handy (at) Objective-Analysis.com

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