How to calculate TBW and DWPD of SSDs?

04.09.2023 | F.A.Q. • Support

How to calculate TBW and DWPD of SSDs?

TBW (Total Bytes Written) - indicates how much data can be written to the drive during the warranty period for the drive to hold its parameters. This is a value calculated based on the DWPD parameter. Very often in the case of SSDs, the manufacturer provides the warranty period or TBW.

How to calculate TBW knowing the DWPD parameter of the drive:

Pattern:

DWPD (Drive Writes Per Day) x disk capacity x 365 days (1 year) x (length of warranty)

Example drive:

HDS-M2T-MTFDDAK1T9TGB1BC - Micron 5400 MAX 1.92TB, SATA, 2.5", 3D TLC, 5DWPD, 7mm

Calculations:

5DWPD x 1920GB x 365 x 5 = 17.52 PBW (TBW in PB)

DWPD (Drive Writes Per Day) - indicates the number of information that can be written each day to not reach the TBW limit before the end of the warranty.

Method 1

Pattern:

disk capacity TB x 1000 / 365 days x how many years x disk capacity GB

Example drive:

HDS-M2T-MTFDDAK1T9TGB1BC - Micron 5400 MAX 1.92TB, SATA, 2.5", 3D TLC, 5DWPD, 7mm

Calculations:

DWPD = 16700 x 1000 / 365 x 5 x 1920GB
17520000 / 3504000
DWPD = 5

Method 2

Pattern:

DWPD = TBW dysku w GB / okres gwarancji w dniach

Example drive:

HDS-M2T-MTFDDAK1T9TGB1BC - Micron 5400 MAX 1.92TB, SATA, 2.5", 3D TLC, 5DWPD, 7mm

Calculations:

17520000 / 1825 = 9600GB dziennie = 9600 / 1920 = 5 DWPD

Summary

For business applications, TBW and DWPD metrics are important when choosing SSDs:

For read-only or OS-only disks, the DWPD parameter can be ~1 DWPD.
For disks where writing is done frequently 75:25% (Write:Read), this parameter should be at least 3DWPD.
For applications where writing takes place all the time and data is continuously overwritten, this parameter should be at least 10DWPD

The above values are only illustrative and the determination of the required DWPD or TBW parameter should be based on real demand.

Currently, you can find Enterprise drives on the market:

<0.5 DWPD (HDS-IUN0-SBFPF2BU038T Solidigm D5-P5430 3.84T PCIe 4x4 QLC U.2 15mm < 0.5 DWPD)
~1 DWPD (HDS-TMN-KXG80ZNV512G Kioxia XG8 512GB NVMe M.2 22x80mm <1DWPD, HF, RoHS)
1.5 DWPD (HDS-M2T-MTFDDAK480TGA1BC Micron 5400 PRO 480GB, SATA, 2.5", 3D TLC, 1.5DWPD, 7mm)
<2 DWPD (HDS-I2T0-SSDSC2KB960GZ Intel D3 S4520 960GB SATA 6Gb/s 3D TLC 2.5" 7.0mm <2DWPD)
3 DWPD (HDS-S2T0-MZ7L31T9HBNAA7 Samsung PM897 1.9TB SATA 6Gb/s TLC 2.5" 7mm 3DWPD 5YR SED)
5 DWPD (HDS-M2T-MTFDDAK480TGB1BC Micron 5400 MAX 480GB, SATA, 2.5", 3D TLC, 5DWPD,7mm)
10 DWPD (HDS-X2A-XS1600ME70045 Seagate Cooper 1.6TB SAS 12Gb/s, 2.5", 15mm, 10DWPD SSD)
30DWPD (HDS-IUN0-SSDPE21K750GAX Intel 3DXPoint P4800X 750G NVMePCIe3.0 2.5" 15mm 30DWPD Rev2)
60DWPD (HDS-IUN0-SSDPE21M375GAX Intel 3DXPoint P4800X 375G NVMePCIe3.0 2.5" 15mm 60DWPD)
100DWPD (HDS-IUN0-SSDPF21Q800GB Intel 3DXPoint DC P5800X 800Gb NVMe PCIe 4.0x4 U.2 15mm 100DWPD)