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Slow backup

Posted: 2019/10/30 06:04:30
by aussie
Hello,

I have two identical machines except one is running Centos 6 and one running Centos 7. When copying small files to the backup disc Centos 7 slows down to 18 MB/sec while copying the identical files to the same backup disc on Centos 6 I get 62 MB/sec.

I tried a backup on a virtual machine running Centos 7 before the upgrading and it was slower, but thought it was due to the virtual machine overhead. After upgrading one of the machines, I now can definitely state it is slower.

Has anyone else experienced the same problem?

Aussie

Re: Slow backup

Posted: 2019/10/30 09:30:37
by TrevorH
How is the backup disk attached?

Re: Slow backup

Posted: 2019/10/30 09:43:14
by aussie
Hi TrevorH,

The backup disk is attached by USB 3.0
It is a 4TB Seagate drive.

Aussie

Re: Slow backup

Posted: 2019/10/30 09:50:25
by TrevorH
If you check dmesg, is it connecting as USB3. Or better, install usbutils and run lsusb.py and see what that tells you about the speed of that device connection.

Re: Slow backup

Posted: 2019/10/30 12:03:15
by aussie
Hi Trevor,

dmesg show lots of errors.
[177817.666333] ehci-pci 0000:05:01.2: port 3 resume error -19
[177817.692321] ehci-pci 0000:05:01.2: port 3 resume error -19
[177817.718319] ehci-pci 0000:05:01.2: port 3 resume error -19
[177817.718359] usb usb3-port3: connect-debounce failed
[177817.718384] ehci-pci 0000:05:01.2: port 4 resume error -19
[177817.920315] ehci-pci 0000:05:01.2: port 4 resume error -19
[177817.920338] usb usb3-port4: over-current condition
[177817.946313] ehci-pci 0000:05:01.2: port 4 resume error -19

dmesg on my Centos 6 system doesn't show over-current and it is the same drive.
I'm not sure what is going on!

I think I'll install Centos 6 over the Centos 7 system and see if I'm still getting errors. I don't know if I have a hardware problem or if it is the Centos 7 system.

Thanks for your suggestion
Aussie

Re: Slow backup

Posted: 2019/10/30 13:03:24
by TrevorH
Two things from that spring out: first it's using ehci not xhci so it's USB 2 not USB 3.

The over-current thing, I'd try sticking it behind a powered USB hub and see if that helps.

Re: Slow backup

Posted: 2019/11/05 06:49:50
by aussie
Hi TrevorH,

I was worried about the backup with all the errors displayed by dmesg. But I verified using sha256sum and the backup is fine.
I is any wonder why the backup is slow, using the USB2 driver instead the the USB3 driver. I tried lsusb.py and it hangs and has to be aborted. But lsusb and lsusb -t work fine. I have 2 USB3 ports from the motherboard and 2 USB3 ports from a pci-e card plugged into the motherboard. These look like bus 7 and bus 9 from the lsusb listings. It has xhci as the driver for both the motherboard usb and the card usb, so I don't know why it is using the ehci driver. I have included listings from lsusb.

Code: Select all

lsusb -t
/:  Bus 09.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 5000M
    |__ Port 2: Dev 3, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/:  Bus 08.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 480M
/:  Bus 07.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 5000M
/:  Bus 06.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 480M
/:  Bus 05.Port 1: Dev 1, Class=root_hub, Driver=ohci-pci/2p, 12M
/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=ohci-pci/3p, 12M
/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/5p, 480M
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M
        |__ Port 2: Dev 3, If 0, Class=Mass Storage, Driver=usb-storage, 480M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
        |__ Port 5: Dev 3, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
        |__ Port 5: Dev 3, If 1, Class=Human Interface Device, Driver=usbhid, 1.5M
        |__ Port 6: Dev 4, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
lsusb
Bus 002 Device 003: ID 14cd:168a Super Top 
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 009 Device 003: ID 1058:0748 Western Digital Technologies, Inc. My Passport (WDBKXH, WDBY8L)
Bus 009 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 008 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 007 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 006 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 1c4f:0048 SiGma Micro 
Bus 001 Device 003: ID 046d:c31c Logitech, Inc. Keyboard K120
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
BTW lsusb.py completes normally on Centos 6, but hangs and has to be aborted on Centos 7.

Aussie

Re: Slow backup

Posted: 2019/11/14 00:02:30
by aussie
Hello,

I have had a breakthrough. All the errors messages in dmesg happen after the machine is resumed from a suspend. If the machine is booted from scratch there are no error messages in dmesg. Including the over-current condition.

I discovered this basically by accident when I upgraded my second computer to Centos 7. After the upgrade of the second machine I did a dmesg and there were no error messages. I thought the first machine must have a hardware problem. Today I did a dmesg on the second machine and it too had error messages. So I thought over what was different. I did a suspend last night and resumed out of the suspend this morning. I tried it and this is the problem.

Problem solved: I was thinking about the errors in dmesg and it was listing USB port 5. I have an Adaptec, 5 port USB2 card. It is a PCI card. I removed this card and all the errors are gone. Centos 6 never had a problem with this card, so it must be change in the driver. I'll submit a defect.

Aussie

Re: Slow backup

Posted: 2019/11/23 01:41:52
by aussie
Hello,

Here is the defect that was filed.
https://bugzilla.redhat.com/show_bug.cgi?id=1775520

Aussie