Hi Vladimir,

> On Thursday 05 October 2006 12:07, you wrote:
>> Hi all,
>>
>> I'm having severe problems with reiserfsck --rebuild-tree on a
>> CryptoLoop over LVM over RAID5 over ENBD (Enhanced Network Block Device)
>> device. The first pass is no problem (finds errors, but runs perfectly),
>> but the second pass hangs my whole system (load increasing to values
>> like 30, 40, 50) after being active for about 20 minutes. 
> 
> Please be precise: which pass hangs? Pass 1 or pass 2? 
> Note that reiserfsck --rebuild-tree starts with pass 0.
I'm sorry: it hangs during the second pass, which is indeed called "pass 1".

> Please clarify what does "hangs whole system" mean. If the system hangs so 
> that it has to be hard rebooted -
Like I said: loads increases dramatically and renders the machine unusable.

> it is very likely that your problem has nothing to do with reiserfsck.
I do think it has something to do with reiserfsck, since the system was
functioning fine until I had to repair my filesystem! I've tried it for
many times now, but it hangs every time during the rebuild-tree.

> If reiserfsck just consumes 100% CPU on pass2 - there is experimental version 
> of reiserfsck which improves pass 2 performance
> substantially in some cases. 
It's not a matter of CPU usage, it's about I/O. I suspect that ReiserFS
fills my memory (TCP buffers) faster than they can flush, which causes
starvation of the buffers.

>> Attached, 
>> you'll find two graphs of this behaviour.
>>
> I see nothing attached.
I think the mailing list doesn't support attachments, but there's not
much too see anyway. Just a graph indicating an increasing load.

However, thanks for your thoughts!

 -- Bas



>> We're talking about a cluster of 5 machines, 4 of them are filled with
>> in total about 3TB of harddisks, the 5th one imports those devices using
>> ENBD and performs 4x RAID5 over it. LVM combines those 4 arrays to one
>> device, and the cryptoloop over LVM ensures safe storage. In the normal
>> situation, there should a mount point /backups (from /dev/loop0) with
>> 2.4TB total space.
>>
>> However, about a week ago I added a new RAID-array to LVM, and started
>> resizing my /backups partition to the maximum available space within
>> LVM. During this resize, my new RAID5-array dropped out due to a disk
>> failure (I didn't let md finish syncing the array...) and the resize
>> failed. At that point, I had a corrupt filesystem, and I'm trying to run
>> reiserfsck --rebuild-tree for a week now.
>>
>> I don't know exactly what is happening, but someone hinted me that
>> reiserfsck might be filling up my TCP buffers (remember, it's a
>> networked block device!) which will lock-up all the I/O to the network
>> block device.
>>
>> For your information: I'm running Debian Sarge with a 2.6.17 kernel from
>> Debian Etch and reiserfsprogs version 3.6.19 from Debian Sarge. The 5th
>> system (frontend) contains a P4 3.0GHz and 1GB of RAM.
>>
>> Has anyone seen something like this before? Or does someone have an idea
>> how I can solve this problem? Might it be worth a try to "upgrade" to
>> Reiser4? If there's no other way, I am willing to give up my data
>> (there's a partial backup of this backup anyway), but I do need to be
>> sure that this won't happen again!
>>
>> BTW, I didn't find out how to subscribe to this list, so please cc. me
>> in your reply! Thanks!
>>
>> Regards,
>>
>>  -- Bas van Schaik
>>

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