Ask ReiserFS Project Leader Hans Reiser 343
Hans Reiser leads a successful Free Software project that has attracted plenty of attention, many users, and even that Holy Grail of so many who have started their own Free or Open Source projects: Big-time funding from DARPA, SuSE, and others. How did he do it? What's his advice for other project leaders? Ask him! And ask him any other question you have in mind. Please stick to one question per post, and avoid questions that can be answered with a few minutes' worth of research. We'll publish Mr. Reiser's answers as soon as he gets them back to us.
Name... (Score:3, Funny)
3 Questions for Open Source Project Management (Score:5, Interesting)
Re:Name... (Score:3, Funny)
More to the point - and I've checked but not found it - how do you pronounce 'reiserfs'?
What is the future of ReiserFS... (Score:5, Interesting)
Re:What is the future of ReiserFS... (Score:5, Informative)
EXT3 is a journaling addition to EXT2, and much more interesting for people who want to change their existing file systems instead of creating new file systems. Note that EXT3 is slower than both ReiserFS and EXT2, but it does have journaling, and provides faster reboots
The main competitor for performance is SGI's excellent XFS. The latest implementations are quite solid, and the performance likewise are excellent. Even compared to ReiserFS.
Both ReiserFS and XFS suffer from the potential of data loss on system failures, and XFS probably more so than ReiserFS, as tiny files might not be committed at all. However, for RAID users, I can not see any reason to use ReiserFS instead of XFS, and definitely not EXT3 unless upgrading the file system.
Regards,
--
Arthur Hagen
Re:What is the future of ReiserFS... (Score:2)
I can. ReiserFS is included in current stable-series kernels, while XFS is not, hence XFS users have to rely on a non-standard, patched kernel.
Re:What is the future of ReiserFS... (Score:3, Informative)
Re:What is the future of ReiserFS... (Score:3, Informative)
Even though ext3 is a journaling filesystem, it still does a lengthy (and annoying) filesystem check every 20 mounts or so. To its credit it has never found an error, but still. I thought getting rid
Re:What is the future of ReiserFS... (Score:3, Informative)
I personally think that the occasional check is probably a good idea, but if it annoys you then you can always change the interval, or even disable it.
Just use "tune2fs -c <how many mounts>
-c 0 should cause it to not use that f
Re:What is the future of ReiserFS... (Score:2, Informative)
Just go to http://oss.sgi.com/projects/xfs/patchlist.html [sgi.com] and pick up the patch against 2.4.20. Works very well for me. All the releases get you is a bunch of release notes and rpms against RedHat kernels. I always get these patches which come out very promptly after the stock kernel release and work very well.
Other uses of Ext3 (Score:2)
Why ReiserFS? (Score:5, Interesting)
Re:Why ReiserFS? (Score:4, Interesting)
Re:Why ReiserFS? (Score:2)
Re:Why ReiserFS? (Score:2, Informative)
I also like the way it's designed it's written so that you can put modules in it. Say you want
Re:Why ReiserFS? (Score:3, Informative)
Integrity of data? Er, please read up on ext3 - a journelling filesystem, same as reiserfs, that seems to have the same (or slightly better) filesystem integrity as reiserfs.
The correct answer would be along the lines that reiserfs is better at handling some files then ext3 - especially small files. I have a ton of text files on an 80 gig shared drive - all small files. Since I'm using ext3, a lot of space is being wasted.
Re:Why ReiserFS? (Score:3, Informative)
Re:Why ReiserFS? (Score:2, Interesting)
Sorry if I sound trollish or anything, but your post sounded kind of like the circular-logic linux trolls around here. "Why is linux better?" "Because it's linux." "Uh, yeah, but WHY?" "It's better because it's the best!"
Good business planning (Score:5, Interesting)
Now you just need to hire someone to desire a modern, more "commercially pleasing" website. =)
Re:Good business planning (Score:3, Informative)
Among his cus
ReiserFS and laptops (Score:5, Interesting)
Re:ReiserFS and laptops (Score:5, Informative)
In fact, I disable access time tracking on every box I work with. I haven't found a worthwhile reason to ever enable it. And that's my 2 cents!
Re:ReiserFS and laptops (Score:3, Informative)
Before turning off atime, I advise that an effort is made to identify what data really needs atime, and if possible create separate partitions for those, with atime enabled.
Regards,
--
*Art
Re:ReiserFS and laptops (Score:3, Informative)
The default PHP session handler uses the atime of the files to expire them properly. If they don't have atime, they get expired prematurely. (I think... It's been a while since I made the mistake of noatime on the partition that holds the session files.)
My solution to this is to use noatime everywhere except the
Re:ReiserFS and laptops (Score:2, Informative)
The Access Time attribute can yield some useful clues to what was going on during an attack when you are doing a forensic analysis. Sure, there are plenty of other things to look at before you get that deep into things, but it's still useful to have sometimes!
Re:ReiserFS and laptops (Score:2)
Guideposts? (Score:5, Interesting)
So here we go ... (Score:4, Interesting)
You've probably noticed that there are quite a few journaling file systems for Linux and other Open/Free/Unixie operating systems that are fairly open or completely open source. Have you ever thought about getting together and making "THE" journaling filesystem for these free OS's? I know that open source is all about choice, but as you probably also know there are certain things EXT3, XSF, etc. can do that ReiserFS cannot. If their could be a hybrid made from the big journaling filesystems would you be part of it?
Another reiser4 (Score:2, Interesting)
Re:Another reiser4 (Score:3, Informative)
--Hans has said in the past that he believes filesystems should be re-written from scratch every few years, so they can take advantage of algorithm improvements and new concepts.
Hash collisions (Score:5, Interesting)
Although its speed and (otherwise) good level of data integrity is of great interest to my employers, before I can recommend it to such a large company, I would like to know how and when you intend to put in a fix.
Re:Hash collisions (Score:2, Insightful)
Re:Hash collisions (Score:2)
Maybe this is why data like prescriptions shouldn't be stored in a filesystem. And I was just starting to think that filesystems were starting to get to the point where that attitude should be revisited. Maybe with XF
Re:Hash collisions (Score:2)
Scroll down are you should see the following:
Re:Hash collisions misquote (Score:3, Interesting)
Re:Hash collisions (Score:3, Informative)
The tricky thing about solving the hash problem (in cryptography) is finding a value that when hashed matches a given string. Here, we are saying that given several hundred thousand keys, what is the probability that any two of them hash to the same value.
The probability is far enough from zero to be a significant danger. Just because hashtables and on
Actually: no... (Score:2)
Re:Actually: no... (Score:2)
Product (2^128-x)/(2^128) for X over [1..N].
I don't trust my intuition on how big that is as N increases; what are the actual numbers?
Comment removed (Score:5, Interesting)
Re:Large Vendor Support (Score:2)
Why did you bother? (Score:5, Interesting)
Does Reiser4 have a chance merging into 2.6? (Score:5, Interesting)
Future of File Systems (Score:5, Interesting)
Can you clarify your long term goals with respect to ReiserFS and file system design in geek lay man's terms?
I'm refering to your Future Vision paper in particular. How would this kind of system be used on a day to day basis?
Right now any mention here of adding database like functionality to a file system is met with crude comments about SQL... Some explaination would really help.
cheers,
--
Simon
Re:Future of File Systems (Score:2)
How about merging Reiser with PostgreSQL?
Undelete (Score:2, Interesting)
Database-like features (Score:5, Interesting)
Reiserfs vs. ext3 (Score:5, Interesting)
So fo me, today, in terms of usability ext3 == reiserfs + ext2 backward compatibility. As much as I hate to admit it, I have now given up on reiserfs.
So my questions are : can you compare reiserfs and ext3 in terms of performance and reliability, i.e. are there good reasons to keep using reiserfs ? Do you think ext3 might become the de-facto standard for Linux journaling filesystems ? How would you feel about it, after all the work you've done on reiserfs ?
Versioning (Score:5, Interesting)
Several research systems have been created, like the Elephant File System [princeton.edu], but none of them made it into the mainstream free and commercial operating systems. Are there any specific reasons why nobody offers recovery (high complexity in implementation, very bad effect on performance, etc) or is it just because FS designers don't see the need for it?
speed with many many small files (Score:5, Interesting)
Filesystems and metadata (Score:5, Interesting)
In your Future Vision white paper [namesys.com], last modified in January 2001, you outline several very interesting ideas about metadata.
Several developements have taken place since : the extensible attributes of BeFS has been burried with BeOS, the database-like metadata of Longhorn (aka Yukon) may actually be a separate layer from the filesystem altogether, and Apple is also moving all metadata out of the filesystem to XML files shared between applications (see iLife package).
My question : What is your current take on the metadata debate ? Do you still think the filesystem is the right place to handle metadata ? Any predictions ?
Snapshots? (Score:5, Interesting)
Re:Snapshots? (Score:3, Interesting)
I haven't used it in a production environment yet, but I've experimented with it and it seemed to work well.
Re:Snapshots? (Score:2)
Why the difference (Score:3, Informative)
reiser4 plugins (Score:5, Interesting)
A question that's interested me for some time… (Score:5, Interesting)
- Minimizing Inner/Outer fragmentation
- Maximising locality of reference
- Minimizing the cost of file extension
I'd like to know how Reiser FS approached these conflicting goals. Has Reiser FS used any mathematical models to evaluate long-term stability/performance?Double-edged sword of DARPA Funding (Score:3, Interesting)
Journalling everything (Score:2)
where next? (Score:5, Interesting)
Reiser FS is already a pretty mature, stable, usable product. Once V4 is done, is there really much work left to be done on ReiserFS proper? Do you have a giant to-do list that'll keep you and the guys occupied for years, or do you intent to work in a diffent direction (SAN, networkFS, databases, etc.)?
(or perhaps you'll just retire to Portugal and play lots and lots of golf)
Starting Large Free Software Projects (Score:5, Interesting)
Naming (Score:2, Interesting)
Re:Naming (Score:2)
I wish I had a couple of moderator points right now, because this is a really interesting question that has a much bigger answer than a simple egotistical reply. It is a stor
Re:Naming (Score:3, Informative)
Raising Awareness (Score:5, Interesting)
Did you use traditional PR techinques, or just through a community of connections?
OpenBSD (Score:3, Interesting)
A simple and obvious question. (Score:5, Interesting)
What's the best way to get funding for a project, assuming the project is at some sort of usable prototype stage already (i.e. who should you approach, what ground work should be done)? How should one court potential sponsors? Is it better to wait for them to come to you, or should you present a formal funding request in a format similar to that of a traditional business plan?
Trade offs (Score:4, Interesting)
ReiserFS 4 vs. MS "SQL-FS" (Score:5, Interesting)
Extended Attributes on Unix (Score:5, Interesting)
I personally have pondered about this a lot. What do you think needs to be adapted and why? Should the VFS be changed? Should traditional Unix tools like "cat" be adapted somehow, or given attribute-aware equivalents? Should file attributes be accessable at the file descriptor level? Will we need a new "tar"? What should be done to standardize these attributes, or make them compatible across filesystems?
Unix filesystem layout (Score:5, Interesting)
The directory layout of the typical unix filesystem has grown over the years to what has become the FHS 2.0.
If you were in the position of designing an entirely new FHS, more suited to ReiserFS (lots of small files, database-like access, etc) and without backward compatibility, what would it look like?
Rules of thumb (Score:5, Interesting)
TELL ME!
Re:Rules of thumb (Score:3, Funny)
Bad block handling! (Score:2, Interesting)
I lost three partitions of data that were formatted with ReiserFS and I was unable to repair them. Creating an image of a partition is simply unacceptable IMHO as part of a data recovery process, suppose you have 600GB of data?
As a newbie (Score:3, Interesting)
What features do you feel are most important/would convince a newbie to make ReiserFS the system to use as compared to the many other alternatives (XFS,EXT3,etc...) out there?
Deadlocking? (Score:5, Interesting)
Re:please name names. (Score:3, Interesting)
"I've spoken to a few people (not naming names) who appear convinced that the design of ReiserFS is fundamentally flawed, and that it would lead to inevitable deadlocking. I've read your white papers now several times (took me a while to figure them out), and think the work you're doing is great, but a few smart people seem to think it can't be trusted."
lets have the names behind those specific claims you posted. lets hear who the smart people are.
fighting the wrong battle? (Score:5, Interesting)
On being one of those "outspoken" people (Score:5, Interesting)
You fall into an interesting subcategory of project managers or whatever you want to call them. I'll call it the "outspoken genius" category (even though the first word might be understated and the last is probably hyperbole). Basicly your work is technically interesting, applicable, etc. That's a give in. But there are quite a few people who have personal issues with you and your manner and usually cite some exchange or another. Sometimes this is the basis of an argument to reject the use of your work, which I think is somewhat silly. You're not the only one, and certainly not the first to be interviewed here.
So what do you think about this? ie. Do you think you made interpersonal mistakes that landed you here or do you think you've been misunderstood? Does it bother you? Why do you think people enjoy egging on folks such as yourself and then citing the moment you get annoyed with them? Do you think this question ever has a prayer of being moderated higher than someone following the method of the previous question?
Jeeze, I realize I just wrote an essay question in the style of one of my old Philosophy professors. You know the kind, here's a statement now write some stuff (I guess I'll give you a few ideas of where to go).
Research? The devil you say... (Score:2)
That's awful big talk from a
How did you get the funding (Score:3, Interesting)
Also, do you known if there is any company that dedicates itself to help Open Source projects, besides de FSF?
Thanks in advance
Distributed Filesystems (Score:3, Interesting)
Filesystems like Coda and InterMezzo, network RAID applications like ENBD/FR1 and DRBD, and filesystem synchronizers like Unison provide some partial solutions for the need to have a distributed filesystem with replication and disconnected operation. Do you think Reiser4 or its successor will provide features which make it easier to implement a robust usable distributed filesystem?
version control in ReiserFS? (Score:5, Interesting)
I recall a discussion at lkml about the licensing issues with bitkeeper. Someone said that the future versions of your FS will have some version control built-in, and thus be a sort-of competitor to Larry McVoy's bitkeeper. Larry's comment was that if that happens, then you have to buy bk in order to use it. [google.ca]
You suggested that indeed version control is going to be in. [google.ca] Can you say more about these plans now, and the eventual conflict with bitkeeper.
Thanks.
Researching filesystems (Score:5, Interesting)
I'm preparing by reading everything I can find: I'm working on Tanenbaum & Woodhull's "OS Design & Implementation"; I've read "Design and Implementation of the Second Extended Filesystem"; Steve Pate's "UNIX Filesystems" is waiting on my shelf; and of course, there's the FAQ and ReiserFS v.3 Whitepaper at www.namesys.com [namesys.com].
Specific questions: what branches of math are useful in this line of research? Any books, articles, etc., that I haven't listed that are a 'must read' or 'should read'? Those who have succeeded in building a better filesystem: what have they done that I should also do? Any mistakes I should avoid? Anything that no one told you about filesystems that you wish you had known up front? And are there any special tricks (above and beyond mastering your subject) to getting hired in this field once a degree is in hand?
Thanks!
Features vs. reliability (Score:3, Interesting)
One very very important question. (Score:3, Informative)
Non-Journalled, or Unsure:
Journalled:
Network file-systems
To summarize: We have a horribly-large number of filesystems, most of which are incompatiable, many of which do not support the Linux security module extensions, one (e2fs) provides defragging under Linux, and none at all provide support for conversions.
Hey, diversity is good! I -like- diversity! I want MORE diviersity! I also want ways to efficiently move data around.
Will future versions of ReiserFS include additional userland tools for defrag, fs conversion, scope of logging (eg: none, meta, full), pluggable hashing algorithm, etc?
Ultimately, all the choice in the world is no choice at all if there's no way to make use of those choices.
Supporting applications (Score:5, Interesting)
Where BeOS failed (among other reasons) because of the perceived lack of applications, do you have any thoughts on how to seed development for ReiserFS.
Case in point, where in other filesystem setups you would have a mail spool and/or mailbox as a custom file format (and indexes) on top of the filesystem, Resier4 allows for custom queryable file attributes (metadata) and the ability to efficiently store each message in the queue as a separate file. The mail handling program becomes proportionally less complex as that complexity has been shifted toward the common filesystem layer.
That said -- mostly for the sake of folks that haven't been following Reiser4 development -- do you see a way of encouraging Reiser4-aware programs? After all, it's a chicken and egg issue. Without common usage of Reiser4, application developers will be less inclined to commit their time to it (perhaps?). Without applications that take advantage of its unique features, what reason does the user have to put it on their workstation or server?
Are we looking at custom Linux distributions with this in mind or just piecemeal applications? Personally, I'm looking forward to dropping Ogg Vorbis files into a directory and, through the use of plugins, having their ID3 info automatically searchable. Hmmm... Where was that Fugees song again?
Performance metrics (Score:4, Interesting)
I'd be curious to see both small file test, large file tests, and a mixture -- as is the case for websites with movies where the HTML and graphics are 3K but the media files are 50MB and up.
Location (Score:3, Interesting)
reiserfs fud (Score:5, Interesting)
Among other claims I have heard by the FUDsters - 'no large production systems (eg terabyte or larger) trust their data to reiserfs', 'xfs is superior to reiserfs because it has been well tested on irix', 'reiserfs has chronic data corruption problems', etc. Spin tactics that would make microsoft's propaganda teams proud.
How do you respond to the FUDsters? What claims are bogus, and what valid objections to reiserfs are there? (The only legitimate problem I can think of - lack of full data journaling - is shared by xfs and jfs as well).
There also seems to be a resistance by commercial distros to adopting reiserfs.
What do you attribute the resistance to?
Re:reiserfs fud (Score:3, Insightful)
all i see is a plain, matter-of-fact notification of a license violation.
reading the thread (which you apparently hoped i wouldn't) I see some less-than-civil [debian.org] replies [debian.org] from debian listmembers, and an apparent admission by other members that debian was indeed [debian.org] in apparent [debian.org] license violation [debian.org].
Is it safe? (Score:3, Funny)
Let me have a look at that tooth. Oh, you've got a cavity. Here let me ...
Aaaaaghhhhhh!!!!!!!
Now, is it safe?
When do you expect it to be released? (Score:2, Informative)
"Reiser4 is due June 30, 2003!"
Re:debian-devel (Score:3, Interesting)
Re:debian-devel (Score:2)
2 words - Bull, china.
You don't just charge in with all-out accusations, you politely ask and see if something can be worked out.
Re:debian-devel (Score:3, Funny)
Re:debian-devel (Score:2)
While Reiser's posting was far from friendly, the only hostility and name-calling seems to come from debian developers.
These things simply happen when ego's clash. Debian developers seem to have a collective huge ego, and Reiser has some prettig large ego by his own.
Live with it. It helps you enjoy the wonderful filesystem called ReiserFS.
Re:debian-devel (Score:2)
In the interest of accuracy, could you restate "huge" and "pretty large" in the current Proposed Standard of Ego Measurement [slashdot.org]?
Re:debian-devel (Score:2)
But the license he is using is the GPL. Hans wants to further restrict the GPL so that he can spam users of his filesystem with advertizements for his sponsors and company. Further, it seems that he's incredibly interested in making sure HE gets credit but doesn't really care for acknowledging the work of others.
So my question is, if you don't like the way the GPL is worded and don't f
Re:Am I ever going to get my coffee? (Score:2)
http://216.239.37.100/search?q=cache:NCAs60dUpskJ : web.gnu.walfield.org/mail-archive/linux-kernel/200 0-August/0356.html+zappe+reiser&hl=en&ie=UTF-8 [216.239.37.100]
The replies:
http://216.239.37.100/search?q=cache:5SyM_97NyeoJ: web.gnu.walfield.org/mail-archive/linux-kernel/200 0-August/0581.html+&hl=en&ie=UTF-8 [216.239.37.100]
Re:Reiser4 (Score:3)