我正在运行 Debian 10，并且有 3 个 SSD，其中一个是 m.2 (nvme)，在两个内部 SSD 之间甚至在同一个 SSD 之间复制文件时，我遇到了一个奇怪的问题：复制 (r/w) 速度永远不会超过 30 Mb/s。在永久 USB 驱动器之间复制或移动文件的速度约为 100 Mb/s。然而，通过检查hdparm，我得到了以下结果：
light@jupiter:~$ sudo hdparm -tT --direct /dev/sda1
/dev/sda1:
Timing O_DIRECT cached reads: 956 MB in 2.00 seconds = 477.68 MB/sec
Timing O_DIRECT disk reads: 1516 MB in 3.00 seconds = 504.67 MB/sec
和
light@jupiter:~$ sudo hdparm -I /dev/sda1
/dev/sda1:
ATA device, with non-removable media
Model Number: Samsung SSD 850 EVO 500GB
Serial Number: S3R3NF1JB20052B
Firmware Revision: EMT03B6Q
Transport: Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6, SATA Rev 3.0
Standards:
Used: unknown (minor revision code 0x0039)
Supported: 9 8 7 6 5
Likely used: 9
Configuration:
Logical max current
cylinders 16383 16383
heads 16 16
sectors/track 63 63
--
CHS current addressable sectors: 16514064
LBA user addressable sectors: 268435455
LBA48 user addressable sectors: 976773168
Logical Sector size: 512 bytes
Physical Sector size: 512 bytes
Logical Sector-0 offset: 0 bytes
device size with M = 1024*1024: 476940 MBytes
device size with M = 1000*1000: 500107 MBytes (500 GB)
cache/buffer size = unknown
Form Factor: 2.5 inch
Nominal Media Rotation Rate: Solid State Device
Capabilities:
LBA, IORDY(can be disabled)
Queue depth: 32
Standby timer values: spec'd by Standard, no device specific minimum
R/W multiple sector transfer: Max = 1 Current = 1
DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6
Cycle time: min=120ns recommended=120ns
PIO: pio0 pio1 pio2 pio3 pio4
Cycle time: no flow control=120ns IORDY flow control=120ns
Commands/features:
Enabled Supported:
* SMART feature set
Security Mode feature set
* Power Management feature set
* Write cache
* Look-ahead
* Host Protected Area feature set
* WRITE_BUFFER command
* READ_BUFFER command
* NOP cmd
* DOWNLOAD_MICROCODE
SET_MAX security extension
* 48-bit Address feature set
* Device Configuration Overlay feature set
* Mandatory FLUSH_CACHE
* FLUSH_CACHE_EXT
* SMART error logging
* SMART self-test
* General Purpose Logging feature set
* WRITE_{DMA|MULTIPLE}_FUA_EXT
* 64-bit World wide name
Write-Read-Verify feature set
* WRITE_UNCORRECTABLE_EXT command
* {READ,WRITE}_DMA_EXT_GPL commands
* Segmented DOWNLOAD_MICROCODE
* Gen1 signaling speed (1.5Gb/s)
* Gen2 signaling speed (3.0Gb/s)
* Gen3 signaling speed (6.0Gb/s)
* Native Command Queueing (NCQ)
* Phy event counters
* READ_LOG_DMA_EXT equivalent to READ_LOG_EXT
* DMA Setup Auto-Activate optimization
Device-initiated interface power management
* Asynchronous notification (eg. media change)
* Software settings preservation
Device Sleep (DEVSLP)
* SMART Command Transport (SCT) feature set
* SCT Write Same (AC2)
* SCT Error Recovery Control (AC3)
* SCT Features Control (AC4)
* SCT Data Tables (AC5)
* reserved 69[4]
* DOWNLOAD MICROCODE DMA command
* SET MAX SETPASSWORD/UNLOCK DMA commands
* WRITE BUFFER DMA command
* READ BUFFER DMA command
* Data Set Management TRIM supported (limit 8 blocks)
Security:
Master password revision code = 65534
supported
not enabled
not locked
frozen
not expired: security count
supported: enhanced erase
2min for SECURITY ERASE UNIT. 8min for ENHANCED SECURITY ERASE UNIT.
Logical Unit WWN Device Identifier: xxxxxxxxxxxxx (EDITED)
NAA : 5
IEEE OUI : 002538
Unique ID : xxxxxxxx (EDITED)
Device Sleep:
DEVSLP Exit Timeout (DETO): 50 ms (drive)
Minimum DEVSLP Assertion Time (MDAT): 30 ms (drive)
Checksum: correct
这些是我的 SSD：
light@jupiter:~$ sudo fdisk -l
Disk /dev/nvme0n1: 232.9 GiB, 250059350016 bytes, 488397168 sectors
Disk model: Samsung SSD 960 EVO 250GB
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: BF245E1A-0824-4270-B4DA-2A3C20CFEB82
Device Start End Sectors Size Type
/dev/nvme0n1p1 2048 1050623 1048576 512M EFI System
/dev/nvme0n1p2 1050624 421918719 420868096 200.7G Linux filesystem
/dev/nvme0n1p3 421918720 488396799 66478080 31.7G Linux swap
Disk /dev/sda: 465.8 GiB, 500107862016 bytes, 976773168 sectors
Disk model: Samsung SSD 850
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 6CA2B8F4-5167-4DC2-B732-5F5754A2043D
Device Start End Sectors Size Type
/dev/sda1 2048 976773119 976771072 465.8G Linux filesystem
Disk /dev/sdb: 465.8 GiB, 500107862016 bytes, 976773168 sectors
Disk model: Samsung SSD 850
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: F16043FD-A05C-4993-BB2E-B241D66C6E77
Device Start End Sectors Size Type
/dev/sdb1 2048 976773119 976771072 465.8G Linux filesystem
和一个硬盘（不知道这是否重要）
Disk /dev/sdc: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors
Disk model: ST2000DM001-1ER1
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0x3ab64096
Device Boot Start End Sectors Size Id Type
/dev/sdc1 2048 3907026943 3907024896 1.8T 7 HPFS/NTFS/exFAT
欢迎任何建议！