ext2fs now extremely slow

[Doug Barton]

On 11/10/2010 09:07, Aditya Sarawgi wrote:
> On Tue, Nov 09, 2010 at 04:20:05PM -0800, Doug Barton wrote:

>> Can you expand on that? What about it do you see as problematic?
>>
>
> ext2fs is not a native filesystem. It is relatively slower than UFS

Like I already said, I can live with a little bit slower.

> may have some other problems like deadlocks which are not yet discovered.

What better way to discover them than actual day to day use? :)

> May make the data inconsistent due to lack of facilities like journaling.

Well that's just plain unacceptable. Either the fs works reliably (which 
obviously includes safely) or it should be removed. At bare minimum if 
it can't reliably write data then support should be changed to read-only.

> It is only meant to make your data in linux partitions accessible.

Sorry, I'm not buying that. Don't get me wrong, I really appreciate the 
help you're providing, and I don't want to get you in the middle of my 
own personal vendetta, but we can't tolerate this perspective. We either 
need to support something, or not support it.

>>>>> You can test Zheng's preallocation patch for ext2fs, there is a
>>>>> serious lack of testers for that.
>>>>
>>>> I would be happy to do that, but my reading of this thread last month
>>>> didn't produce a clear "try this version of the patch" neon sign.
>>>> Various people referred to suggestions, updates, etc. If someone could
>>>> provide a URL for the right patch to try, as well as a suggestion for
>>>> benchmarking methodology, I'll be glad to do so.
>>>>
>>>
>>> I have attached the patch.
>>
>> Thanks for that. I'm curious though whether this is the latest version
>> of the patch with the suggested improvements from earlier in this thread?
>>
>
> There will be only style and some comment fixes in the new patch.

Ok, thanks.

> Yes, we know there are some scope of improvements. So the BSDL ext2fs lacks
> preallocation which used to preallocate some blocks which improved the sequential
> write performance. This problem is solved by Zheng's reservation window work.
> The other issue like Bruce mentioned is that some of the blocks in between are
> skipped by the block allocator algorithm. We intend to have fixes for both of
> these before 9 is released.

Ok, but time is running out. :)


Doug

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