On Sep 28, 2010, at 4:00 PM, Thomas Kula wrote:

> On Tue, Sep 28, 2010 at 12:49:59PM -0700, Russ Allbery wrote:
>> Jeff Blaine <[email protected]> writes:
>> 
>>> Barring an equivalent, what Linux setup...
>> 
>>>  a) seems most stable
>>>  b) is fsck-less
>> 
>>> Even quick grunt responses are appreciated.
>> 
>> We use ext3.  It isn't the fastest or the most featureful, but it's the
>> core file system that everyone uses on Linux and for us it's been rock
>> solid.  You're the least likely to run into strange problems.
> 
> We (umich.edu) also use ext3. We randomly run into issues where 
> the filesystem half-thinks that things that should be files are
> directories, which, when this happens on a vice paritition, leads
> to interesting problems. 
> 
> Other co-workers (some of whom I believe are on this list) follow
> this more, but I think our strategy has been to keep on top of any
> kernel issues and the corresponding userspace tools for dealing with
> ext filesystems and see what those do. I have no idea why we tend
> to run into this with not-frequent-but-too-often-for-me regularity.
> 
> That said, I'm not sure what else we'd even consider running on
> Linux systems.

*raises hand as 'other co-worker'*

Yep, we're pretty much a 100% ext3 shop. We keep a close eye on other things, 
and zfs has been looking more and more interesting. But given the uncertain 
state of its future (see elsewhere in this thread) our caution level has gone 
up quite a bit. For the really long term I also keep an eye on btrfs, but some 
of it's features aren't as big a win for AFS as they are for 'regular' users. 
Ext4 looks interesting just for the fsck speed improvements (just freaking 
amazing). Extents may also be useful, but I strongly suspect other issues 
bottleneck AFS performance before the filesystem speed does. Then again, better 
speed never hurts.

Tom refers to some ext3 problem with directories suddenly becoming files or 
vice-versa. There are two points worth mentioning here. First, it is extremely 
rare - maybe once every six months. That's in a cell with 26 file servers, 64 
vice partitions, 260,000 volumes, 180M files, 92TB of raw space for AFS with 
46TB currently used, compounded growth rate of about 45% per year. Big. Second, 
we are running our own linux-from-scratch systems. It's quite possible we have 
introduced a frailty somewhere.

We have several times been bitten in the ass by ext3 bugs, and the recovery 
process has not been pretty. Usually we've traced this down to actual ext3 bugs 
that others have found and fixed; I've not yet recently made that chase on our 
dir-vs-file problem. For all I know, it's oAFS hosing up an inode somehow. But 
without having equivalent data about what other sites do and their 
size/configurations, I can't honestly say if our problems are unique to us or 
just somethings that most folks manage to run below the radar on.

But either way we'll be sticking to ext3 for at least the next couple of years.

Steve_______________________________________________
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