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IDProjectCategoryView StatusLast Update
0006231CentOS-6sssdpublic2013-01-31 21:56
Reporterfrodri 
PrioritynormalSeveritymajorReproducibilityalways
Status newResolutionopen 
Product Version6.3 
Target VersionFixed in Version 
Summary0006231: SSHD freezes/jitters randomly
DescriptionI have setup two identical x86_64 headless servers running Centos 6.3. When I access the servers via ssh, either through the local LAN or through the Internet, the session becomes unresponsive at random intervals, ranging from one or two seconds to >1 minute. Just to be clear, the sessions are not disconnecting, they just become completely unresponsive as in what I type in does not appear on screen during the lag (but does afterwards), and if running top the refresh stops. This happens equally in both servers. Other network services (httpd and nfs) appear to be unnafected during these blackouts. Disruption seems to increase while using the terminal, so it becomes impossible to operate the machine remotely after some time.

Steps To ReproduceInstall Centos 6.3 and sshd in a server; then login remotely using ssh. Random freezes will start to occur, typically after a couple of minutes of activity in the terminal.

Freezes occur more often when:
   -Hitting ENTER to run a command (the screen does not print the whole line before the ENTER until after the freeze)
   -When using the backspace; or arrow up to bringup the previous line.
Additional InformationI have setup a script to monitor networking connectivity in the machines (I log failed ping requests, to the other internal server and to an external server (OPenDNS), and no loss of connectivity is apparent during the blackouts.

Accessing http pages served from the same computer while ssh is frozen, will sometimes (but not always) unblock the ssh terminal.


Additionally see the following files:


ifconfig
eth0 Link encap:Ethernet HWaddr 90:2B:34:69:10:31
          inet addr:192.168.0.10 Bcast:192.168.0.255 Mask:255.255.255.0
          inet6 addr: fe80::922b:34ff:fe69:1031/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
          RX packets:5234103 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1145500 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:6807382581 (6.3 GiB) TX bytes:798110034 (761.1 MiB)
          Interrupt:24 Base address:0xe000

lo Link encap:Local Loopback
          inet addr:127.0.0.1 Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING MTU:16436 Metric:1
          RX packets:31816 errors:0 dropped:0 overruns:0 frame:0
          TX packets:31816 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:17349135 (16.5 MiB) TX bytes:17349135 (16.5 MiB)


lspci:

00:00.0 Host bridge: Advanced Micro Devices [AMD] nee ATI RD890 PCI to PCI bridge (external gfx0 port B) (rev 02)
00:02.0 PCI bridge: Advanced Micro Devices [AMD] nee ATI RD890 PCI to PCI bridge (PCI express gpp port B)
00:09.0 PCI bridge: Advanced Micro Devices [AMD] nee ATI RD890 PCI to PCI bridge (PCI express gpp port H)
00:0a.0 PCI bridge: Advanced Micro Devices [AMD] nee ATI RD890 PCI to PCI bridge (external gfx1 port A)
00:11.0 SATA controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 SATA Controller [IDE mode] (rev 40)
00:12.0 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB OHCI0 Controller
00:12.2 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB EHCI Controller
00:13.0 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB OHCI0 Controller
00:13.2 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB EHCI Controller
00:14.0 SMBus: Advanced Micro Devices [AMD] nee ATI SBx00 SMBus Controller (rev 42)
00:14.1 IDE interface: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 IDE Controller (rev 40)
00:14.2 Audio device: Advanced Micro Devices [AMD] nee ATI SBx00 Azalia (Intel HDA) (rev 40)
00:14.3 ISA bridge: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 LPC host controller (rev 40)
00:14.4 PCI bridge: Advanced Micro Devices [AMD] nee ATI SBx00 PCI to PCI Bridge (rev 40)
00:14.5 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB OHCI2 Controller
00:15.0 PCI bridge: Advanced Micro Devices [AMD] nee ATI SB700/SB800/SB900 PCI to PCI bridge (PCIE port 0)
00:15.1 PCI bridge: Advanced Micro Devices [AMD] nee ATI SB700/SB800/SB900 PCI to PCI bridge (PCIE port 1)
00:15.2 PCI bridge: Advanced Micro Devices [AMD] nee ATI SB900 PCI to PCI bridge (PCIE port 2)
00:15.3 PCI bridge: Advanced Micro Devices [AMD] nee ATI SB900 PCI to PCI bridge (PCIE port 3)
00:16.0 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB OHCI0 Controller
00:16.2 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB EHCI Controller
00:18.0 Host bridge: Advanced Micro Devices [AMD] Family 15h Processor Function 0
00:18.1 Host bridge: Advanced Micro Devices [AMD] Family 15h Processor Function 1
00:18.2 Host bridge: Advanced Micro Devices [AMD] Family 15h Processor Function 2
00:18.3 Host bridge: Advanced Micro Devices [AMD] Family 15h Processor Function 3
00:18.4 Host bridge: Advanced Micro Devices [AMD] Family 15h Processor Function 4
00:18.5 Host bridge: Advanced Micro Devices [AMD] Family 15h Processor Function 5
01:00.0 VGA compatible controller: NVIDIA Corporation GT218 [GeForce 210] (rev a2)
01:00.1 Audio device: NVIDIA Corporation High Definition Audio Controller (rev a1)
02:00.0 USB controller: Etron Technology, Inc. EJ168 USB 3.0 Host Controller (rev 01)
03:00.0 IDE interface: Marvell Technology Group Ltd. 88SE9172 SATA III 6Gb/s RAID Controller (rev 11)
04:0e.0 FireWire (IEEE 1394): VIA Technologies, Inc. VT6306/7/8 [Fire II(M)] IEEE 1394 OHCI Controller (rev c0)
05:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)
06:00.0 USB controller: Etron Technology, Inc. EJ168 USB 3.0 Host Controller (rev 01)



dmesg gives:

Linux version 2.6.32-279.19.1.el6.x86_64 (moc build@c6b8.bsys.dev.centos.org) (gcc version 4.4.6 20120305 (Red Hat 4.4.6-4) (GCC) ) #1 SMP Wed Dec 19 07:05:20 UTC 2012
Command line: ro root=/dev/mapper/vg_olmeca-LogVolRoot rd_NO_LUKS rd_LVM_LV=vg_olmeca/LogVolRoot LANG=en_US.UTF-8 rd_MD_UUID=f8317674:04455f89:a6cc276f:6b8679c1 SYSFONT=latarcyrheb-sun16 crashkernel=auto KEYBOARDTYPE=pc KEYTABLE=us rd_MD_UUID=4b0c8744:351f4846:960015bc:56beda47 rd_NO_DM rhgb quiet
KERNEL supported cpus:
  Intel GenuineIntel
  AMD AuthenticAMD
  Centaur CentaurHauls
BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009f800 (usable)
 BIOS-e820: 000000000009f800 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 00000000bfda0000 (usable)
 BIOS-e820: 00000000bfda0000 - 00000000bfdd1000 (ACPI NVS)
 BIOS-e820: 00000000bfdd1000 - 00000000bfe00000 (ACPI data)
 BIOS-e820: 00000000bfe00000 - 00000000bff00000 (reserved)
 BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
 BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)
 BIOS-e820: 0000000100000000 - 000000043f000000 (usable)
DMI 2.4 present.
SMBIOS version 2.4 @ 0xF10E0
DMI: Gigabyte Technology Co., Ltd. GA-990FXA-UD3/GA-990FXA-UD3, BIOS F8 05/30/2012
e820 update range: 0000000000000000 - 0000000000001000 (usable) ==> (reserved)
e820 remove range: 00000000000a0000 - 0000000000100000 (usable)
last_pfn = 0x43f000 max_arch_pfn = 0x400000000
 

(have truncated rest; happy to post if needed)
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Date Modified Username Field Change
2013-01-31 21:56 frodri New Issue