Hi Eugen,
Quoting a document on IO-Hintig:
'Storage vendors can also supply "I/O hints" about a device's preferred
minimum unit for random I/O ('minimum_io_size') and streaming I/O
('optimal_io_size'). For example, these hints may correspond to a RAID
device's chunk size and stripe size respectively.'
Of course a RAIDs layout parameters and preferred IO sizes are
semantically completely different things.
As for your case:
Ignore the warning. I think the optimal IO size as in 'preferred size
for sequential streaming IO' is indeed correct and must not necessarily
be a multiple of physical sector size. The optimal IO size is owed to
the transport layer (USB protocol) constraints, to max out the BUS
bandwidth.
Cutting it down to a simple example:
Consider each frame in the transport layer can hold 1.9 physical
sectors. Stuffing only 1 sector into the frame (to keep the multiple
physical sector constraint) will lead to a significant rise in number of
frames/packets and thus overhead. And I am not even talking about
transport layers with fixed frame size where you'll loose nearly 50% of
bandwidth and therefore transfer rate.
Anyway, in your case everything seems properly aligned. I tried to find
a way to influence 'optimal_io_size', could not find anything. Changing
the parameters via sysfs does not work, maybe there are IOCTLs and a
suiting utility...
Regards
-Sven
Am 10.01.2016 um 18:22 schrieb Eugen Rogoza:
My personal opinion is: The test is semantically wrong in different
aspects. May I ask what drive you are using and what interface it uses?
Regards
-Sven
Hi Sven,
drive info below:
root@nuc:~> hdparm -I /dev/sdc
/dev/sdc:
ATA device, with non-removable media
Model Number: WDC WD60EZRX-00MVLB1
Serial Number: WD-WX41D94RNKAX
Firmware Revision: 80.00A80
Transport: Serial, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6, SATA Rev 3.0
Standards:
Used: unknown (minor revision code 0x001f)
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:11721045168
Logical Sector size: 512 bytes
Physical Sector size: 4096 bytes
device size with M = 1024*1024: 5723166 MBytes
device size with M = 1000*1000: 6001175 MBytes (6001 GB)
cache/buffer size = unknown
Nominal Media Rotation Rate: 5700
Capabilities:
LBA, IORDY(can be disabled)
Queue depth: 32
Standby timer values: spec'd by Standard, with device specific minimum
R/W multiple sector transfer: Max = 16 Current = 0
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
Power-Up In Standby feature set
* SET_FEATURES required to spinup after power up
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
* 64-bit World wide name
* 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)
* Host-initiated interface power management
* Phy event counters
* NCQ priority information
* unknown 76[15]
DMA Setup Auto-Activate optimization
Device-initiated interface power management
* Software settings preservation
* SMART Command Transport (SCT) feature set
* SCT Write Same (AC2)
* SCT Features Control (AC4)
* SCT Data Tables (AC5)
unknown 206[12] (vendor specific)
unknown 206[13] (vendor specific)
* DOWNLOAD MICROCODE DMA command
* WRITE BUFFER DMA command
* READ BUFFER DMA command
Security:
Master password revision code = 65534
supported
not enabled
not locked
not frozen
not expired: security count
supported: enhanced erase
Logical Unit WWN Device Identifier: 50014ee20b2a3e40
NAA : 5
IEEE OUI : 0014ee
Unique ID : 20b2a3e40
Checksum: correct
It is an internal 3,5" SATA-drive put into a USB3-enclosure and connected via USB3 in UAS mode:
Jan 10 01:13:26 nuc kernel: usb 2-4: new SuperSpeed USB device number 2 using xhci_hcd
Jan 10 01:13:26 nuc kernel: usb 2-4: New USB device found, idVendor=174c, idProduct=55aa
Jan 10 01:13:26 nuc kernel: usb 2-4: New USB device strings: Mfr=2, Product=3, SerialNumber=1
Jan 10 01:13:26 nuc kernel: usb 2-4: Product: ASM1153E
Jan 10 01:13:26 nuc kernel: usb 2-4: Manufacturer: asmedia
Jan 10 01:13:26 nuc kernel: usb 2-4: SerialNumber: 1234567891C4
Jan 10 01:13:26 nuc kernel: scsi host4: uas
Jan 10 01:13:26 nuc kernel: usbcore: registered new interface driver uas
Jan 10 01:13:26 nuc kernel: scsi 4:0:0:0: Direct-Access ASMT 2115 0 PQ: 0 ANSI: 6
Jan 10 01:13:26 nuc kernel: sd 4:0:0:0: Attached scsi generic sg2 type 0
Jan 10 01:13:26 nuc kernel: sd 4:0:0:0: [sdc] Spinning up disk...
Jan 10 01:13:27 nuc kernel: ............ready
Jan 10 01:13:38 nuc kernel: sd 4:0:0:0: [sdc] 11721045168 512-byte logical blocks: (6.00 TB/5.45 TiB)
Jan 10 01:13:38 nuc kernel: sd 4:0:0:0: [sdc] 4096-byte physical blocks
Jan 10 01:13:38 nuc kernel: sd 4:0:0:0: [sdc] Write Protect is off
Jan 10 01:13:38 nuc kernel: sd 4:0:0:0: [sdc] Mode Sense: 43 00 00 00
Jan 10 01:13:38 nuc kernel: sd 4:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
Jan 10 01:13:38 nuc kernel: sdc: sdc1 sdc2 sdc3 sdc4
Jan 10 01:13:38 nuc kernel: sd 4:0:0:0: [sdc] Attached SCSI disk
As a side note: sdc4 was a dm-crypt/LUKS-encrypted partition before. To my knowledge the device mapper warnings started to appear after migration to VeraCrypt.
Cheers,
Eugen
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