Table of Contents

HDD
- Examples
  - WD
SSD

HDD

LMR - Longitudal Magnetic Recording
CMR/PMR - Conventional Magnetic Recording / Perpendicular Magnetic Recording
- Tech from 2000. Normal tracks but vertical orientation. 3x density gain
SMR - Shingled Magnetic Recording (overlapping tracks)
- Trick to buffers write. Some small SSD memory, some space on platers are used for “journal” with fast CMR access, then disk is using idle time to rewrite it into SMR area. This can be very problematic during huge write load - e.g. RAID rebuild. So keep 20% of disc empty.

Where to check:

Rules:

Don't buy Seagate DM (Barracuda) discs at all

Examples

Seagate
- Barracuda 2-6TB should be SMR
  - ST2000DM008-2FR102 - Barracuda 2TB = SMR ←- poor drive, it slowns downs all writes and start clicking after few months
  - ST4000DM004 4TB - Barracuda SMR
  - ST8000DM004 8TB - Barracuda Compute 5400rpm = SMR
- IronWolf still CMR
  - ST2000VN004-2E4164 - IronWolf 2TB = CMR / native 512B
  - ST4000VN006 4TB - IronWolf CMR
- ST1000NM0033-9ZM173 - Constellation ES.3 = CMR
- ST2000NM0008-2F3100 - Enterprise Capacity 2TB = CMR
- ST1000VX005 1TB - SkyHawk Surveillance - CMR
- ST2000VX008 2TB - SkyHawk Surveillance - CMR
- ST2000VX015 2TB - SkyHawk Surveillance - SMR

Toshiba
- 1 to 6TB - SMR
- X300, P300, N300 - CMR
- Toshiba HDWD120 - Desktop P300 - PMR
- Toshiba HDWD220EZSTA 2TB - Desktop P300 - SMR!
- Toshiba HDWV110UZSVA 1TB - Surveillance S300 - CMR
- Toshiba HDWT720UZSVA 2TB - Surveillance S300 - SMR
- Toshiba DT01ACA200 - 2TB - CMR

WD

WD
- WDC_WD2005FBYZ-01YCBB3 - WD Gold (for NAS/Raid) - CMR
- WD Red 3,5“ (WD20EFAX, WD30EFAX, WD40EFAX, WD60EFAX)- SMR
- WD Blue 3,5”
  - SMR: WD20EZAZ, WD40EZAZ, WD60EZAZ, WD30EZAZ, WD20EZBX, WD20EZAZ
  - CMR: WD80EAZZ, WD60EAZAX, WD40EZAX, WD30EZAX, WD20EARZ, WD20EZRZ, WD10EZRZ, WD10EZEX, WD5000AZRZ, WD5000AZLX
- WD Blue 2.5“ (WD10SPZX, WD20SPZX) - SMR
- WD Black 2,5” (WD10SPSX) - SMR
- WD22PURZ - Purple 2TB / 256MB cache, 5400 rpm - CMR
  - WD Purple is recommended by community for CCTV
- WD42PURZ - Purple 4TB / 256MB cache, 5400 rpm - CMR
- WD10EFRX..WD60EFRX - CMR
- WD80EFAX = CMR
- WD101EFAX, WD120EFAX, WD140EFFX - CMR

HGST
Ultrastar 7K4000
- HGST HUS724020 ALS640 - Ultrastar 7K4000 3.5-Inch Enterprise 7200 RPM Hard Disk Drives
  - 7200 rpm, 64MB, 3,5“, SAS 6Gb/s
  - MTBF1 2.0 million hours
  - Ultrastar 7K4000 represents the sixth-generation HGST 5-platter design
  - Data Buffer (MB) 64
  - Rotational Speed (RPM) 7200
  - Interface Transfer Rate (MB/s, Max) 600
  - Sustained Transfer Rate (MB/s, Typical) 183
  - Seek Time (Read, ms, typical) 8.0

SSD