Raid5 resync freezes system

Raid5 resync freezes system

[Jens Kübler]

Hello there
Here is what I got:

Abit KT7 Raid 
First IDE Controller is a Via
Second IDE controller is a HPT370 just using the ide part and NOT THE RAID 
PART of it
Duron 750
192MB RAM (fully tested using memtest)
Western Digital WDC WD1200BB-00CAA1 (120GB)
Maxtor 4D080H4 (80GB)
Maxtor 96147H6 (60GB)
Maxtor 5T060H6 (60GB)

using Mandrake 9.1 with Kernel 2.4.21-00
before this Mandrake 9.0 with kernel 2.4.19

Each disk parts with 60GB in the software raid5 array.

If I create the array, the system starts to resync the four disks. After an 
arbitrary time the resync freezes the system. I have tried to create an array 
with only three of the disks to exclude any damaged hd, I have switched ide 
ports and there was still no effect. Then I played a bit with the 
/proc/sys/dev/raid/  values and lowered the max_value as I thought this could 
be due to heavy IO load which was at 12MB. First I reduced it to 5MB/s but it 
was still crashing. The test with 2MB/s is currently underway.
During these many resyncs I've seen so far the speed sometimes stayed at 4MB/s 
without having any IO on the system. 
The computer itself is well cooled espacially the harddisks.

If the system does not crash during boot (it is also starting the resync 
there) I will shut down the device and the system is stable even if I create 
some heavy IO load.

The reiserfs I created seems to have nothing to do with these crashes as they 
occured with and without the created file system.

In hope of help.

Jens

Re: Raid5 resync freezes system

[Jorg de Jong]

Jens Kübler wrote:
> Hello there
> Here is what I got:
> 
> Abit KT7 Raid 
> First IDE Controller is a Via
> Second IDE controller is a HPT370 just using the ide part and NOT THE RAID 
> PART of it
> Duron 750
> 192MB RAM (fully tested using memtest)
> Western Digital WDC WD1200BB-00CAA1 (120GB)
> Maxtor 4D080H4 (80GB)
> Maxtor 96147H6 (60GB)
> Maxtor 5T060H6 (60GB)
> 
> using Mandrake 9.1 with Kernel 2.4.21-00
> before this Mandrake 9.0 with kernel 2.4.19
> 
> Each disk parts with 60GB in the software raid5 array.
> 
> If I create the array, the system starts to resync the four disks. After an 
> arbitrary time the resync freezes the system. I have tried to create an array 
> with only three of the disks to exclude any damaged hd, I have switched ide 
> ports and there was still no effect. Then I played a bit with the 
> /proc/sys/dev/raid/  values and lowered the max_value as I thought this could 
> be due to heavy IO load which was at 12MB. First I reduced it to 5MB/s but it 
> was still crashing. The test with 2MB/s is currently underway.
> During these many resyncs I've seen so far the speed sometimes stayed at 4MB/s 
> without having any IO on the system. 
> The computer itself is well cooled espacially the harddisks.
> 
> If the system does not crash during boot (it is also starting the resync 
> there) I will shut down the device and the system is stable even if I create 
> some heavy IO load.
> 
> The reiserfs I created seems to have nothing to do with these crashes as they 
> occured with and without the created file system.
> 
> In hope of help.
> 
> Jens

Hi Jens,

what you describe sound very mutch what I am experiencing as well.

My setup is:
MSI K7D ( SMP board with two AMD MP2000 cpu's)
1 Gig ram (fully memtested)
1st onbord ide controler
2nd ide controler RocketRAID 404 controler ( is a HPT374 just using the
ide part and NOT THE RAID) (running at 66 MHZ)
3rd ide controler promise PDC20267 ( running at 33 MHZ)
3 identical seagate ST360021A 60 Gb (part of raid array)
1 seagate ST360015A 60 Gb ( part of raid array)
1 seagate ST340823A contains root filesystem always connected to 1st ide controler

running RedHat 8.0 kernel 2.4.18-27.8.0smp ( and other redhat rolled kernels)

Setup where all raid disk are connected to HPT374 controller:
When the raid array is synced this setup seems stable, althow I see random lockups
about once a month. If the raid array needs syncing it almost never compleets. I see
lockups during boot, during starting of X-windows, after 15 minutes uptime, ect.
I also had a disk that contained bad sectors. During raid reconstruction this was
never reported. After replacing the bad disk, the array still would not reconstruct.
I did not have the impression IO-load had anything to do with it. Even in
single user mode it would lockup. On other occasions I could do heavy IO-load during
reconstruction without the system being locked up.

I therfore switched backt to a setup were all raid disk where connected to the
PDC20267 controller.
Only in this setup my bad disk was dectected and thrown out of the raid array.
After replacing the bad disk the raid array was reconstructed successfully.
I cant say I have never experienced lockups in this setup but feels mutch more stable.


In all setups I use mostly reiserfs on top of LVM on top of a raid5 md.
I to feel that reiserfs and LVM have noting to do with it since lockups occur
even in single usermode where the filesystems where not mounted and LVM was not
loaded.

After reading about your problems and seeing the you also use a HighPoint controller
is would suspect that it might be that the HighPoint controller is to blame ?!


regards,

Jorg de Jong










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