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Slow HDD diagnostics

I have 4 external drives connected to my rpi4b (4G). 1 is a WD Blue SSD co nnected to usb3 port with the rootfs. The other 3 are HDDs connected throu gh an USB3 hub to the other rpi usb3 port. One of the HDDs is much slower than the other drives. What are some diagnostice commands I could use to t ry to diagnose why the drive is slower than the others?

Here are results of lsusb and hdparm outputs with my comments in { }.

pi@rpi4b:~ $ lsusb Bus 002 Device 003: ID 059f:1065 LaCie, Ltd Bus 002 Device 004: ID 0bc2:ab28 Seagate RSS LLC Bus 002 Device 005: ID 152d:1561 JMicron Technology Corp. / JMicron USA Tec hnology Corp. JMS561U two ports SATA 6Gb/s bridge Bus 002 Device 002: ID 2109:0815 VIA Labs, Inc. Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 008: ID 05ac:921d Apple, Inc. Bus 001 Device 005: ID 05ac:911d Apple, Inc. Bus 001 Device 010: ID 05ac:020b Apple, Inc. Pro Keyboard [Mitsumi, A1048/U S layout] Bus 001 Device 007: ID 03f0:134a HP, Inc Optical Mouse Bus 001 Device 004: ID 05ac:1003 Apple, Inc. Hub in Pro Keyboard [Mitsumi, A1048] Bus 001 Device 006: ID 0080:a001 Bus 001 Device 003: ID 2109:2815 VIA Labs, Inc. Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

pi@rpi4b:~ $ sync; sync; sudo hdparm -t /dev/sda /dev/sda: {4TB 2.5 HDD unknown rpm} SG_IO: bad/missing sense data, sb[]: 70 00 05 00 00 00 00 0a 00 00 00 00 2

4 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Timing buffered disk reads: 342 MB in 3.00 seconds = 114.00 MB/sec

pi@rpi4b:~ $ sync; sync; sudo hdparm -t /dev/sdc /dev/sdc: {8TB 3.5 HDD 5400rpm} Timing buffered disk reads: 100 MB in 3.01 seconds = 33.25 MB/sec

pi@rpi4b:~ $ sync; sync; sudo hdparm -t /dev/sdd /dev/sdd: {3TB 3.5 HDD 7200rpm} Timing buffered disk reads: 388 MB in 3.05 seconds = 127.37 MB/sec

pi@rpi4b:~ $ sync; sync; sudo hdparm -t /dev/sdb /dev/sdb: {WD Blue SSD 2.5 form factor, rootfs} Timing buffered disk reads: 576 MB in 3.00 seconds = 191.87 MB/sec

Why is /dev/sdc so slow runnning through same usb3 hub as /dev/sda and /dev /sdd? I don't think it is rotation speed of drives.

TIA/ --Steven

Reply to
nelsonse48
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On Wed, 17 Mar 2021 10:40:29 -0700 (PDT), " snipped-for-privacy@gmail.com" declaimed the following:

I'd blame rotation speed with a fragmented file system -- fragmentation and head seeks means waiting for the platter to rotate the next desired sector into position.

It's also a larger drive, and if inodes are stored in one area, with data stored elsewhere, and the journal somewhere else, there could be a lot more seeking being performed.

--
	Wulfraed                 Dennis Lee Bieber         AF6VN 
	wlfraed@ix.netcom.com    http://wlfraed.microdiversity.freeddns.org/
Reply to
Dennis Lee Bieber

That speed looks like it is running at USB2 speeds. Are you sure the USB adpapter is USB3? Maybe it's USB2

Reply to
Jim Jackson

Orico SATA3.0 - 6Gbps enclosure {USB3.0+SATA III; Support capacity 16TB; Support UASP} Seagate Barracuda 8TB HDD

It should be as fast as the other drives.

--Steven

Reply to
nelsonse48

Try testing it without other drives connected to that USB hub.

Reply to
Nikolaj Lazic

Filesystem layout isn?t relevant here. ?hdparm -t? doesn?t measure filesystem performance, only raw read.

--
https://www.greenend.org.uk/rjk/
Reply to
Richard Kettlewell

It _should_ be. But it can happen that a fully USB3 configuration can still negotiate only USB2. One of my backup drives used to suffer from this. Have a look at what appears in the kernel log when you connect the drive (I?m afraid I don?t remember exactly what to look for).

--
https://www.greenend.org.uk/rjk/
Reply to
Richard Kettlewell

There are lots of issues with RPI4 and USB3 attached drives - check the forum, especially this _long_ sticky thread ...

formatting link

Always make sure your USB3 A plug is _fully_ pushed into the USB3 A socket - otherwise only the USB2 contacts will engage. The USB3 extra contacts are further back and might not engage.

I have a USB3 attached SSD, and then a powered USB3 hub with 2 disks attached and get reasonable individual speeds on the disks, i.e. more than USB2 speeds. My WD passport 1TB 5400 rpm disks are not super-fast (92MB/sec) but that's to be expected.

Reply to
Jim Jackson

The easy way to do that it the open a console and run:

sudo tail -f /var/log/messages

and then connect the drive. You'll get severa;l log lines that give details about the device that you just plugged in, and what USB type (USB2, USB3) its connecting as.

Kill 'tail' by typing Ctrl/C when you've finished.

--
Martin    | martin at 
Gregorie  | gregorie dot org
Reply to
Martin Gregorie

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