Server suddenly freezes but awakes upon SysRq!?

Server suddenly freezes but awakes upon SysRq!?

[Christian Hammers]

Hello

We have some problems with a server that started to suddenly freeze
every now and then which means that it does react to ping and tcp
connects but does not allow a login nor returns the shell or does syslog
write anything to disc or network.

Funnily it always immediately awakes when we presses 'AltGr+SysGr+h'
although a login on the console did not work before.

What could be the cause of this "sleep" mode if a sysrq ends it?
We noticed that at least 1-2 freezes occured right after accessing the
external usb2.0 backup harddrive.

The server is a dual-p3 with a 3ware ide-scsi RAID and very low load as
postfix+apache server.

bye,

-christian-

Some bits of the configuration:

...
CONFIG_MPENTIUMIII=y
...
CONFIG_HIGHMEM4G=y
# CONFIG_HIGHMEM64G is not set
CONFIG_HIGHMEM=y
CONFIG_HIGHIO=y
# CONFIG_MATH_EMULATION is not set
CONFIG_MTRR=y
CONFIG_SMP=y
CONFIG_NR_CPUS=32
# CONFIG_X86_NUMA is not set
# CONFIG_X86_TSC_DISABLE is not set
CONFIG_X86_TSC=y
CONFIG_HAVE_DEC_LOCK=y
#
# General setup
#
CONFIG_NET=y
CONFIG_X86_IO_APIC=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_PCI=y
# CONFIG_PCI_GOBIOS is not set
# CONFIG_PCI_GODIRECT is not set
CONFIG_PCI_GOANY=y
CONFIG_PCI_BIOS=y
CONFIG_PCI_DIRECT=y
CONFIG_ISA=y
CONFIG_PCI_NAMES=y
# CONFIG_EISA is not set
# CONFIG_MCA is not set
CONFIG_HOTPLUG=y
...
# CONFIG_ACPI is not set
CONFIG_ACPI_BOOT=y
...
CONFIG_PNP=y
CONFIG_ISAPNP=m
...
CONFIG_DEBUG_STACKOVERFLOW=y
# CONFIG_DEBUG_HIGHMEM is not set
# CONFIG_DEBUG_SLAB is not set
# CONFIG_DEBUG_IOVIRT is not set
CONFIG_MAGIC_SYSRQ=y
# CONFIG_DEBUG_SPINLOCK is not set
# CONFIG_FRAME_POINTER is not set
CONFIG_LOG_BUF_SHIFT=0

-- 
Christian Hammers             WESTEND GmbH  |  Internet-Business-Provider
Technik                       CISCO Systems Partner - Authorized Reseller
                              Lütticher Straße 10      Tel 0241/701333-11
ch@westend.com                D-52064 Aachen              Fax 0241/911879

Re: Server suddenly freezes but awakes upon SysRq!?

[Trent Lloyd]

I've seen similar problems where the machines userspace seems to die but
it still pings etc and requires a reboot
This was on just P1/PPRO hardware, never figured it out. havent seen it
for quite some time
Haven't tried SQSRQ, if I see it again I'll try that.

Cheers,
Trent
Sixlabs

> Hello
> 
> We have some problems with a server that started to suddenly freeze
> every now and then which means that it does react to ping and tcp
> connects but does not allow a login nor returns the shell or does syslog
> write anything to disc or network.
> 
> Funnily it always immediately awakes when we presses 'AltGr+SysGr+h'
> although a login on the console did not work before.
> 
> What could be the cause of this "sleep" mode if a sysrq ends it?
> We noticed that at least 1-2 freezes occured right after accessing the
> external usb2.0 backup harddrive.
> 
> The server is a dual-p3 with a 3ware ide-scsi RAID and very low load as
> postfix+apache server.
> 
> bye,
> 
> -christian-
> 
> Some bits of the configuration:
> 
> ...
> CONFIG_MPENTIUMIII=y
> ...
> CONFIG_HIGHMEM4G=y
> # CONFIG_HIGHMEM64G is not set
> CONFIG_HIGHMEM=y
> CONFIG_HIGHIO=y
> # CONFIG_MATH_EMULATION is not set
> CONFIG_MTRR=y
> CONFIG_SMP=y
> CONFIG_NR_CPUS=32
> # CONFIG_X86_NUMA is not set
> # CONFIG_X86_TSC_DISABLE is not set
> CONFIG_X86_TSC=y
> CONFIG_HAVE_DEC_LOCK=y
> #
> # General setup
> #
> CONFIG_NET=y
> CONFIG_X86_IO_APIC=y
> CONFIG_X86_LOCAL_APIC=y
> CONFIG_PCI=y
> # CONFIG_PCI_GOBIOS is not set
> # CONFIG_PCI_GODIRECT is not set
> CONFIG_PCI_GOANY=y
> CONFIG_PCI_BIOS=y
> CONFIG_PCI_DIRECT=y
> CONFIG_ISA=y
> CONFIG_PCI_NAMES=y
> # CONFIG_EISA is not set
> # CONFIG_MCA is not set
> CONFIG_HOTPLUG=y
> ...
> # CONFIG_ACPI is not set
> CONFIG_ACPI_BOOT=y
> ...
> CONFIG_PNP=y
> CONFIG_ISAPNP=m
> ...
> CONFIG_DEBUG_STACKOVERFLOW=y
> # CONFIG_DEBUG_HIGHMEM is not set
> # CONFIG_DEBUG_SLAB is not set
> # CONFIG_DEBUG_IOVIRT is not set
> CONFIG_MAGIC_SYSRQ=y
> # CONFIG_DEBUG_SPINLOCK is not set
> # CONFIG_FRAME_POINTER is not set
> CONFIG_LOG_BUF_SHIFT=0
> 
> -- 
> Christian Hammers             WESTEND GmbH  |  Internet-Business-Provider
> Technik                       CISCO Systems Partner - Authorized Reseller
>                               L?tticher Stra?e 10      Tel 0241/701333-11
> ch@westend.com                D-52064 Aachen              Fax 0241/911879
> 
> -
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