45 ssd selection guide appendix, Step-by-step calculation – Hatteland Display HT B22 (Fanless) User Manual
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45
SSD Selection Guide
Appendix
IND100077-130
Calculation of required size of SSD (Multi-Level Cell - MLC) device)
The table below details the write endurance of the an enterprise environment. All values are verified by Hatteland
Display during the qualification / selection process.
Write Endurance Specifications
Intel® SSD 320 Series
Write Endurance Specifications
Current 2.5” SSD (MLC)
Device Size
Value in TBW (Terabytes)
Device Size
Value in TBW (Terabytes)
40 GB
5
80 GB
45
80 GB
10
120 GB
70
120 GB
15
160 GB
100
160 GB
15
240 GB
140
300 GB
30
300 GB
225
600 GB
60
600 GB
330
Write endurance is measured while running 100%
random 4KB (4096 bytes) writes spanning 100% of
the drive using Iometer.
JESD218 standard1 and based on JESD219 workload.
Formula for calculating disk size:
z
=
y
*
x
Where
y
= Requested minimum lifetime (with respect to wear out, [year]).
Where
x
= Data rate (GB /per year).
Where
z
= Total amount of data written data to SSD during its whole lifetime.
Step-by-Step Calculation
Step 1: Measure (preferred) or estimate data rate
y
, [GB /per year].
Step 2: Define minimum expected lifetime for SSD device
x
[year].
Step 3: Calculate total amount of data written to the SSD during its whole lifetime,
z
=
y
*
x
.
Step 4: Use table,
column 2
, the
z
value shall be less or equal to the value in the table to achieve requested lifetime.
Write Endurance Specifications
Intel® SSD 320 Series
Write Endurance Specifications
Current 2.5” SSD (MLC)
Device Size
Value in TBW (Terabytes)
Device Size
Value in TBW (Terabytes)
40 GB
5
80 GB
45
80 GB
10
120 GB
70
120 GB
15
160 GB
100
160 GB
15
240 GB
140
300 GB
30
300 GB
225
600 GB
60
600 GB
330
Step 5: Select the SSD device,
column 1
, which corresponds to the selected value in
column 2
.
Step 6. Check that the size of the selected SSD is greater than required size of the SSD, if not select the size of the
SSD that match customer requirements.