Re: the " 'official' point of view" expressed by kernelnewbies.orgregarding reiser4 inclusion

From: Jeff V. Merkey
Date: Mon Jul 31 2006 - 19:16:27 EST


Nate Diller wrote:

On 7/31/06, Jeff V. Merkey <jmerkey@xxxxxxxxxxxxxxxxxxxxx> wrote:

Gregory Maxwell wrote:

> On 7/31/06, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
>
>> Its well accepted that reiserfs3 has some robustness problems in the
>> face of physical media errors. The structure of the file system and the
>> tree basis make it very hard to avoid such problems. XFS appears to have
>> managed to achieve both robustness and better data structures.
>>
>> How reiser4 compares I've no idea.
>
>
> Citation?
>
> I ask because your clam differs from the only detailed research that
> I'm aware of on the subject[1]. In figure 2 of the iron filesystems
> paper that Ext3 is show to ignore a great number of data-loss inducing
> failure conditions that Reiser3 detects an panics under.
>
> Are you sure that you aren't commenting on cases where Reiser3 alerts
> the user to a critical data condition (via a panic) which leads to a
> trouble report while ext3 ignores the problem which suppresses the
> trouble report from the user?
>
> *1) http://www.cs.wisc.edu/adsl/Publications/iron-sosp05.pdf

Hi Gregory, Wikimedia Foundation and LKML?

How's Wikimania going. :-)

What he says is correct. I have seen some serious issues with reiserfs
in terms of stability and
data corruption. Resier is however FASTER, but the statement is has
robustness issues is accurate.
I was using reiserfs but we opted to make EXT3 the default for Solera
appliances, even when using Suse 10
due to issues I have seen with data corruption and hard hangs on RAID 0
read/write sector errors. I have
stopped using it for local drives and based everything on EXT3. Not to
say it won't get there eventually, but
file systems have to endure a lot of time in the field and deployment
befor they are ready for prime time.

The Wikimedia appliances use Wolf Mountain, and I've tested it for about
4 months with few problems, but
I only use it for hosting the Cherokee Langauge Wikipedia. It's
performance is several magnitudes better
than either EXT3 or ReiserFS. Despite this, for vertical wiki servers,
its ok to go out with, folks can specifiy
whether they want appliances with EXT3, Reiser, or WMFS, but iit's a
long way from being "cooked"
completely, though it does scale to 1 exabyte FS images.


i've seen you mention the Wolf Mountain FS in other emails, but google
isn't telling me a lot about it. Do you have a whitepaper? are there
any published benchmark results? what sort of workloads do you
benchmark?

NATE

Wikipedia is the app for now. I have not done any benchmarks on the FS side, just the capture side, and its been transferred to
another entity. I have no idea what they are naming it to, but I expect you may hear about it soon. One of the incarnations
of it is Solera's DSFS which can be reviewed here:

www.soleranetworks.com

I can sustain 850 MB/S throughput from user space with it -- about 5 x any other FS. On some hardware, I've broken
the 1.25 GB/S (gigabyte/second) windows with it.

Jeff
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