ext2fs now extremely slow

[Aditya Sarawgi]

On Wed, Nov 3, 2010 at 5:21 AM, Doug Barton <dougb at freebsd.org> wrote:
> On 09/29/10 13:25, Aditya Sarawgi wrote:
>>
>> [snip]
>>>>
>>>> I see what you are saying. The gap of 8 block between the files
>>>> is due to the old preallocation which used to allocate additional
>>>> 8 blocks in advance for a particular inode when allocating a block
>>>> for it. The gap between blocks of the same file shouldn't be there
>>>> too. Both of these cases should be removed. I will look into this
>>>> during this week. The slowness is also due to lack of preallocation
>>>> in the new code.
>>>
>>> One of the GSoC students worked on a patch to add preallocation back to
>>> ext2fs this summer.  Would you be interested in reviewing and/or testing
>>> that patch?  (I've attached it).  Here is his original e-mail:
>>
>> [snip]
>>
>> Hi John,
>>
>> I did a review of Zheng Liu's reservation window patch last week and
>> I suggested him a few changes. Otherwise the code looks awesome.
>> But it would be great if someone else can review the patch too and if
>> everything goes well, we should merge this to HEAD.
>> For the ext4 part, I still have to review his patches and I am planning
>> to do it soon. Zheng is planning to have a separate module for ext4,
>> and it does make sense. We are aiming at bringing ext4 to a usable state
>> for 9-RELEASE (atleast read-only).
>
> Is anything happening with this?  I recently built a new system that is
> multi-booting windows, freebsd, and ubuntu. I chose ext[23]fs for my /home
> partition so that I could share unix'y stuff between freebsd and linux, but
> I'm having both performance and stability problems, and today (fortunately
> for the first time, and fortunately recoverable) I had actual data loss. I'm
> happy to be a guinea pig for new code if people are reasonably sure that it
> will help, but if the situation doesn't improve I will have to reformat.
>

Are you suffering from these problems on CURRENT ? Can you please elaborate
on the performance and stability issue you are facing ? Any specific scenario ?

You can test Zheng's preallocation patch for ext2fs, there is a
serious lack of testers
for that.


> On a related note, is there any way to use the journaling features of ext3fs
> in FreeBSD? When I boot the linux partition it's treating the fs as ext3fs,
> but AFAICS we only have ext2fs capabilities.
>

Journaling is difficult to bring in, especially if one is planning to
have a BSDL
version.

> FWIW, the reason I chose ext2fs is that linux doesn't have reliable r/w
> support for ufs, and there are really good drivers to mount ext2fs
> partitions in windows; which we also don't have for ufs.
>
>
> Doug
>
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>
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-- 
Cheers,
Aditya Sarawgi