AWSBarker
Posts: 7
Joined: Tue Apr 11, 2017 8:56 am

dual docking station, SSD boot , how to use 2nd slot (as backup)

Sat Dec 08, 2018 5:58 pm

I managed to get my 3B+ booting from SSD but I used a USB dual docking station (JMS551).
The 3B+ runs a website, owncloud and file server and its been so stable and fast I don't dare touch it.

Now I had the "smart idea" to make direct backups to the empty slot using old SATA HDD. But the problem is I cannot get the 2nd slot to work at all.

a. If I hot slot an empty EXT4 formatted into slot B, I get a complete freeze, no escape except pull-plug reboot, no logs.
b. If I try a reboot with both slots (A=SSD boot/root, B=empty EXT4) it doesn't boot and no logs.

Does anyone have a trick to get a log so I can start to trouble shoot a solution, or maybe it's not such a smart idea?

Thanks for any guidance.
Andrew

$ lsusb
Bus 001 Device 006: ID 04f2:0402 Chicony Electronics Co., Ltd Genius LuxeMate i200 Keyboard
Bus 001 Device 004: ID 058f:6362 Alcor Micro Corp. Flash Card Reader/Writer
Bus 001 Device 007: ID 046d:c05b Logitech, Inc. M-U0004 810-001317 [B110 Optical USB Mouse]
Bus 001 Device 005: ID 152d:2551 JMicron Technology Corp. / JMicron USA Technology Corp. JMS551 SATA 3Gb/s bridge

$ dmesg | grep JM
[ 2.468480] usb 1-1.1.2: Manufacturer: JMicron

Bus 001 Device 005: ID 152d:2551 JMicron Technology Corp. / JMicron USA Technology Corp. JMS551 SATA 3Gb/s bridge
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x152d JMicron Technology Corp. / JMicron USA Technology Corp.
idProduct 0x2551 JMS551 SATA 3Gb/s bridge
bcdDevice 1.00
iManufacturer 1 JMicron
iProduct 11 USB Mass Storage
iSerial 3 000000000036
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 32
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 4 USB Mass Storage
bmAttributes 0xc0
Self Powered
MaxPower 2mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 8 Mass Storage
bInterfaceSubClass 6 SCSI
bInterfaceProtocol 80 Bulk-Only
iInterface 6 MSC Bulk-Only Transfer
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Binary Object Store Descriptor:
bLength 5
bDescriptorType 15
wTotalLength 42
bNumDeviceCaps 3
USB 2.0 Extension Device Capability:
bLength 7
bDescriptorType 16
bDevCapabilityType 2
bmAttributes 0x00000002
Link Power Management (LPM) Supported
SuperSpeed USB Device Capability:
bLength 10
bDescriptorType 16
bDevCapabilityType 3
bmAttributes 0x00
wSpeedsSupported 0x000e
Device can operate at Full Speed (12Mbps)
Device can operate at High Speed (480Mbps)
Device can operate at SuperSpeed (5Gbps)
bFunctionalitySupport 1
Lowest fully-functional device speed is Full Speed (12Mbps)
bU1DevExitLat 10 micro seconds
bU2DevExitLat 32 micro seconds
Container ID Device Capability:
bLength 20
bDescriptorType 16
bDevCapabilityType 4
bReserved 0
ContainerID {00010203-0405-0607-0800-000000000000}
Device Status: 0x0001
Self Powered

Andyroo
Posts: 1479
Joined: Sat Jun 16, 2018 12:49 am
Location: Lincs U.K.

Re: dual docking station, SSD boot , how to use 2nd slot (as backup)

Sat Dec 08, 2018 6:37 pm

Do you have a link to the enclosure?

Despite Linux supporting hot-plug native and USB supporting hot-plug it does not mean the enclosure will do it :cry:

When you have both disks in do you get any lights at all?

Has the enclosure run with two disks in any system (e.g. Mac / Pc)?
Need Pi spray - these things are breeding in my house...

AWSBarker
Posts: 7
Joined: Tue Apr 11, 2017 8:56 am

Re: dual docking station, SSD boot , how to use 2nd slot (as backup)

Sun Dec 09, 2018 11:27 am

Thanks Andyroo,

The Digitus site doesn't have the info but i found this (https://www.manualslib.com/manual/92430 ... e=2#manual) link to the specs. It confirms the hot-plug capability but no Linux mentioned. However in the past I've used it as USB HDD from Ubuntu and Raspbian.

Mostly I used it as stand-alone HDD to SSD cloning but I recall using Gparted to trim and clone a larger image onto smaller SSD.

I will take the Pi offline and check again for dual-HDD capability when used as external USB dual dock under raspbian/ubuntu but pretty sure it will work.

Normally, when running as Pi boot/root SSD, the dock shows 1 blue light, flashing according to disk access. If I try a hot-plug with 2nd HDD it immediately freezes whole system and no 2nd blue light.

Based on your feedback I try the above again and watch more carefully for any activity.

AWSBarker
Posts: 7
Joined: Tue Apr 11, 2017 8:56 am

Re: dual docking station, SSD boot , how to use 2nd slot (as backup)

Sun Dec 09, 2018 2:13 pm

I ran the above mentioned tests using a RPi3b with Mate and a RpiW with raspbian stretch and both passed:-

a. boot normally (mate/raspbian on SD card) and recognise the dock both slots loaded at boot
b. hot plug and unplug cycle
Also with Ubuntu on a PC the dock and hot-plug cycle works flawless.

So it would seem that by using the dock as boot/root with raspbian SSD in slot A somehow disrupts the normal workings. Without a log I'm out of ideas on what I could change to enable the 2nd slot to function.

Any further ideas?
Andrew

Andyroo
Posts: 1479
Joined: Sat Jun 16, 2018 12:49 am
Location: Lincs U.K.

Re: dual docking station, SSD boot , how to use 2nd slot (as backup)

Sun Dec 09, 2018 2:44 pm

I'll imitate Homer at this point and go 'dhuuu' with a suitable baffled look on my face...

I should have a cable arriving in the post tomorrow that will let me try two disks with a 3B booting from HDD if no one else comes up with anything :lol:
Need Pi spray - these things are breeding in my house...

AWSBarker
Posts: 7
Joined: Tue Apr 11, 2017 8:56 am

Re: dual docking station, SSD boot , how to use 2nd slot (as backup)

Sun Dec 09, 2018 6:27 pm

funny, this whole idea came from somebody testing SSD speeds using USB - SATA cable. Let me know how it goes, I guess I could always buy two of these cables but really liked the idea of the dual dock and single cable.

Tomorrow I'll try and edit to fstab, I can put a line based on the UUID of the slot B HDD, so it gets mounted according to a rule. I just have a feeling it's getting lost during mounting.

Andyroo
Posts: 1479
Joined: Sat Jun 16, 2018 12:49 am
Location: Lincs U.K.

Re: dual docking station, SSD boot , how to use 2nd slot (as backup)

Mon Dec 10, 2018 9:55 pm

Evening,

Sorry to say my cable from Manchester (that far away place more commonly known as China with a new label on it) did not come and I'm back in hospital tomorrow.

As soon as I'm able I'll do the test for you :oops: :cry:
Need Pi spray - these things are breeding in my house...

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