I have a server with a software RAID system.
There are 4 disk in the array:
4 x 4TB model WD40EFRX-68WT0N0
I noticed that the OS was reporting one of the disks to be 3TB, so I rebooted and checked in the BIOS and it also reports 3TB. Whereas it reports 4TB for the others.
The sticker on the physical disk says 4TB, just like the other 3. This disk has been in the server for several months with no problem. The only change I made recently is to update the OS (on a drive outside of the RAID).
I will replace the disk, but was wondering if anyone had seen this before and If there is a fix. Is it likely to be the HDD controller, the motherboard/bios (MSI/AMI), or something else? I put the drive in a different machine, and the BIOS there also reports 3TB.
Why is it exactly 3TB instead of 4? Seems too exact somehow.
more details on the drives: SATA, WD Red(tm), NASware(tm) 3.0
As per @shodanshok's request, here is the output from hdparm and smartctl. Looks like a Host Protected Area is enabled, and uses 1/4 of the drive.
$ sudo hdparm -N /dev/sda /dev/sda: max sectors = 5860577134/7814037168, HPA is enabled
Can this have been set accidentally or by an OS install somehow?
and here's the output from smartctl:
$ sudo smartctl -a /dev/sda smartctl 6.2 2013-07-26 r3841 [x86_64-linux-3.19.0-32-generic] (local build) Copyright (C) 2002-13, Bruce Allen, Christian Franke, www.smartmontools.org === START OF INFORMATION SECTION === Device Model: WDC WD40EFRX-68WT0N0 Serial Number: WD-WCC4E5RZJJUE LU WWN Device Id: 5 0014ee 2b7895291 Firmware Version: 82.00A82 User Capacity: 3,000,615,492,608 bytes [3.00 TB] Sector Sizes: 512 bytes logical, 4096 bytes physical Rotation Rate: 5400 rpm Device is: Not in smartctl database [for details use: -P showall] ATA Version is: ACS-2 (minor revision not indicated) SATA Version is: SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s) Local Time is: Thu Apr 14 13:58:53 2016 IST SMART support is: Available - device has SMART capability. SMART support is: Enabled === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED General SMART Values: Offline data collection status: (0x00) Offline data collection activity was never started. Auto Offline Data Collection: Disabled. Self-test execution status: ( 0) The previous self-test routine completed without error or no self-test has ever been run. Total time to complete Offline data collection: (53280) seconds. Offline data collection capabilities: (0x7b) SMART execute Offline immediate. Auto Offline data collection on/off support. Suspend Offline collection upon new command. Offline surface scan supported. Self-test supported. Conveyance Self-test supported. Selective Self-test supported. SMART capabilities: (0x0003) Saves SMART data before entering power-saving mode. Supports SMART auto save timer. Error logging capability: (0x01) Error logging supported. General Purpose Logging supported. Short self-test routine recommended polling time: ( 2) minutes. Extended self-test routine recommended polling time: ( 532) minutes. Conveyance self-test routine recommended polling time: ( 5) minutes. SCT capabilities: (0x703d) SCT Status supported. SCT Error Recovery Control supported. SCT Feature Control supported. SCT Data Table supported. SMART Attributes Data Structure revision number: 16 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 1 Raw_Read_Error_Rate 0x002f 200 200 051 Pre-fail Always - 0 3 Spin_Up_Time 0x0027 175 175 021 Pre-fail Always - 8241 4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 14 5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0 7 Seek_Error_Rate 0x002e 200 200 000 Old_age Always - 0 9 Power_On_Hours 0x0032 098 098 000 Old_age Always - 1992 10 Spin_Retry_Count 0x0032 100 253 000 Old_age Always - 0 11 Calibration_Retry_Count 0x0032 100 253 000 Old_age Always - 0 12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 14 192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 9 193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 1830 194 Temperature_Celsius 0x0022 114 108 000 Old_age Always - 38 196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0 197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 0 198 Offline_Uncorrectable 0x0030 100 253 000 Old_age Offline - 0 199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0 200 Multi_Zone_Error_Rate 0x0008 100 253 000 Old_age Offline - 0 SMART Error Log Version: 1 No Errors Logged SMART Self-test log structure revision number 1 No self-tests have been logged. [To run self-tests, use: smartctl -t] SMART Selective self-test log data structure revision number 1 SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS 1 0 0 Not_testing 2 0 0 Not_testing 3 0 0 Not_testing 4 0 0 Not_testing 5 0 0 Not_testing Selective self-test flags (0x0): After scanning selected spans, do NOT read-scan remainder of disk. If Selective self-test is pending on power-up, resume after 0 minute delay.