什么是硬盘的SMART？

SMART：是Self-Monitoring Analysis And Reporting Technology的缩写，即自我检测分析与报告技术，成为一种自动监控硬盘驱动器完好状况和报告潜在问题的技术标准。作为技术标准，SMART规定了硬盘制造厂商应遵循的标准，规范主要如下：

1.在硬盘生产阶段完成SMART的属性和参数设定；

2.允许用户开启或关闭SMART功能；

3.在用户使用硬盘过程中，可以根据获取到SMART信息有效判断硬盘的状态，并做出相应的措施或警告；

SMART信息检测了哪些属性？

SMART技术标准定义了常用的硬盘检测参数：

SMART信息怎么查询：

在Linux系统上提供了smartctl工具，可以查看硬盘的基础信息，包括Device Model，SN，Firmware, SMART信息等；

[~#]smartctl -a /dev/sdf
smartctl 6.5 2016-05-07 r4318 [x86_64-linux-3.10.0-957.el7.x86_64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model: HGST HUS728T8TALE6L0
Serial Number: VYG973GS
LU WWN Device Id: 5 000cca 0c6c43209
Add. Product Id: DELL(tm)
Firmware Version: V8DERT06
User Capacity: 8,001,563,222,016 bytes [8.00 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate: 7200 rpm
Form Factor: 3.5 inches
Device is: Not in smartctl database [for details use: -P showall]
ATA Version is: ACS-2, ATA8-ACS T13/1699-D revision 4
SATA Version is: SATA 3.2, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is: Thu Mar 2 20:42:48 2023 CST
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: (0x82) Offline data collection activity
was completed without error.
Auto Offline Data Collection: Enabled.
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: ( 90) seconds.
Offline data collection
capabilities: (0x5b) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
No 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: ( 943) minutes.
SCT capabilities: (0x003d) SCT Status supported.
SCT Error Recovery Control supported.
SCT Feature Control supported.
SCT Data Table supported.

SMART Attributes Data Structure revision number: 16

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Short offline Completed without error 00% 5395 -
# 2 Short offline Completed without error 00% 15 -
# 3 Short offline Completed without error 00% 15 -
# 4 Vendor (0xdf) Completed without error 00% 12 -

# 5 Short offline Completed without error 00% 11 -

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.

smartctl执行结果解读：

菜单栏参数说明：

ATTRIBUTE_NAME：SMART信息的检测项

FLAG：检测项的操作标志

Value：当前值，硬盘运行时实时根据内部公式实际计算出来的值，计算公式由硬盘厂家自行定义，数值会不断刷新；

Worst: 最差值，硬盘运行时各检测项曾出现过的最大的非正常值，数值会实时情况不断刷新；

Threshold：临界值，硬盘厂商指定的表示某一检测项的可靠性门限值，当前值接近阈值时，表示硬盘将变得不可靠，可能出现故障或者数据丢失；

RAW_VALUE：原始值

TYPE：检测项的类型（Pre-fail或Oldage），Pre-fail类型的属性是一个关键属性，表示磁盘的整体SMART健康评估（PASSED/FAILED）。如果任何Pre-fail类型的属性异常，那磁盘将要发生故障。另一方面，Oldage类型的属性为非关键的属性（如正常的磁盘磨损），表示不会使磁盘本身发生故障，只是读写过程中产生的正常磨损。

UPDATED：表示检测项的更新频率，Offline代表磁盘上执行离线测试的时间。

WHEN_FAILED：如果VALUE<=THRESHOLD，会被设置成“FAILING_NOW”；如果WORST<=THRESH会被设置成“In_the_past”；正常情况下会被设置成“-”。

“FAILING_NOW”情况下，需要尽快备份重要文件，尤其属性是Pre-fail类型时；

“In_the_past”代表属性已经故障了，但在运行测试的时候没问题；

“-”代表这个属性从没故障过。