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