tag:blogger.com,1999:blog-7898615.post6085497482603223335..comments2023-08-08T03:26:54.107-04:00Comments on Recording Artist: Don't be a ZFS HaterDrew Thalerhttp://www.blogger.com/profile/01081923007415869973noreply@blogger.comBlogger63125tag:blogger.com,1999:blog-7898615.post-90639671565653020282007-10-13T21:52:00.000-04:002007-10-13T21:52:00.000-04:00Drew wrote: "1. Compression. HFS+ doesn't have any...Drew wrote: "1. Compression. HFS+ doesn't have any built-in support for it. You can do it manually, but it's a lot nicer to just flip a switch to enable it automatically. You may not want to use compression permanently, but it can help relieve pressure when you get tight."<BR/><BR/>Perhaps read-only files could be stored on a compressed disk image. Probably wouldn't work well for images, but would save space taken up by documentation and similar content.<BR/><BR/>If the files are normally in specific locations on the disk, create symlinks from the expected location to the file on the image. Set up the image as something that is opened on login, and Bob's your uncle, unless I'm missing something fundamental about the implementation of compressed images that would make this scheme silly.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-65038982693631507672007-10-11T18:29:00.000-04:002007-10-11T18:29:00.000-04:00By the way, that sort of incremental upgrading isn...By the way, that sort of incremental upgrading isn't sci-fi. A product called <A HREF="http://www.drobo.com/products_demo.aspx" REL="nofollow">Drobo</A> does this kind of live, incremental storage upgrading today.Drew Thalerhttps://www.blogger.com/profile/01081923007415869973noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-89514991089914519032007-10-11T18:27:00.000-04:002007-10-11T18:27:00.000-04:00Travis: No worries, I definitely understand. A com...<B>Travis</B>: No worries, I definitely understand. A commenter on another post pointed me at this post from Eric Kustarz: <A HREF="http://blogs.sun.com/erickustarz/entry/zfs_on_a_laptop" REL="nofollow">ZFS on a laptop?</A> It's got some nifty points.<BR/><BR/>As for reducing storage pressure on a self-contained system like a notebook:<BR/><BR/>1. Compression. HFS+ doesn't have any built-in support for it. You can do it manually, but it's a lot nicer to just flip a switch to enable it automatically. You may not want to use compression permanently, but it can help relieve pressure when you get tight.<BR/><BR/>2. Laptop pools. I mentioned this in a comment above: the future doesn't have to be like the past. With flash getting more popular and larger capacity, a future laptop could use multiple flash drives instead of one big drive. Let's hypothesize two things that don't exist yet, but will probably exist soon: (1) something like <I>zpool remove</I> that migrates all data off an existing drive so that it can be removed, and (2) an ultralight which uses four 64GB flash drives = 256GB pool.<BR/><BR/>Hey, look, the new 128GB flash drives just came out. If we have 64GB of free space, we can just <I>zpool remove</I> one of the 64s and add a 128 in its place. If we don't, we could temporarily add a 64GB external drive to hold the overflow. Need more space? Replace another 64 with a 128. And so on. Incremental hard disk upgrades! Pretty sweet.<BR/><BR/>I don't think RAID-Z lends itself to this sort of setup very well, because afaik it requires identical drives. If there were a intermediate level between "unprotected pool" and "full RAID" which allowed asymmetric setups (without the same level of guaranteed protection, of course), you might even be able to hot-swap drives from smaller to larger.Drew Thalerhttps://www.blogger.com/profile/01081923007415869973noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-12618437672531896042007-10-10T17:40:00.000-04:002007-10-10T17:40:00.000-04:00Derek: Re bug 6458218, see the comment from Matt A...Derek: Re bug 6458218, see the comment from Matt Ahrens (current ZFS team lead) on how to recover from it:<BR/><BR/> To recover from this situation, try running build 60 or later, and put<BR/> 'set zfs:zfs_recover=1' in /etc/system. This should allow you to read<BR/> your pool again. (However, we can't recommend running in this state<BR/> forever; you should backup and restore your pool ASAP.)<BR/><BR/>Some bugs in ZFS have allowed the user to still read their data with kernel hacks, like this one. But because there is no fsck, the recovery mechanism is reformat-and-restore. There is no other way to get back to a consistent on-disk state.<BR/><BR/>Other bugs simply require reformatting the pool and don't allow you to get your data back at all:<BR/><BR/> http://www.mail-archive.com/zfs-discuss@opensolaris.org/msg07796.html<BR/><BR/>-- AntonAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-62613526071161596462007-10-10T17:32:00.000-04:002007-10-10T17:32:00.000-04:00(Sorry if I sounded a bit peeved last post; I've b...(Sorry if I sounded a bit peeved last post; I've been without 'net access since 9/20, and having to access from various public hotspots when I've had opportunity.)<BR/><BR/>It's been a long time since I've done any native-code programming (think TML Pascal, if anyone remembers it :) ), but yes, I'm aware of the need to make tradeoffs; it's still pretty important in the database work I'm doing now. <BR/><BR/>The problem I had with your argument is that it seems to belittle (especially with the crack about floppies) the importance of a tradeoff that is <B>very</B> front-and-center for me, one that I deal with daily, and one that you ignored completely in your reply (as it concentrated on speed and not disk space); as I said, my laptop hard drive is in a state of constant triage, trying to keep 4-6 gig of free working space for the operating system. The best solution I've been able to manage is one of the small bus-powered portable drives, as an archive where I can keep some of the datafiles I don't absolutely need to keep online at any given time, like my image archive. This is not a very good solution, though; the time I move something off into the archive is usually not long before I realize I want to get to it again, and a laptop is used in a lot of places where it's awkward to have an external drive hanging off by a short cable. <BR/><BR/>(This use case is also why I'm wary of the storage pool concept; as others have noted in some of the follow-up articles to your post, it assumes that once you plug a drive into your computer, it stays there. This may be great for servers, but I do a lot of hot-swapping drives around between the desktop and the laptop, hooking the archive to the laptop, and carrying drives back and forth between the office. I used a system where the data on removable storage was added seamlessly to the 'data soup' when you plugged it in, back with the Newton; it was a royal PITA back then.)<BR/><BR/>Moreover, I understand very well the need to look to the future in design - but I don't see any change to this issue in the foreseeable future. This has been a problem with the mass storage on any computer I've had going back to the 5 MB Bernoulli Box I had running on a Mac 512E, to the point where one of my standard maxims is 'The datastore will always expand to fill the space available to it.' So as far as I'm concerned, tradeoffs involving the use of significant amounts of disk space are not trivial, and I don't see them ever becoming trivial, in anything but a relative fashion. (25K may have been a huge tradeoff in the days of 400K floppies, but it's trivial today; however, we're not talking about 25K here, are we?)<BR/><BR/>It's interesting to read Rick Schaut's comments on this in his blog entry on the Word 6.0 debacle. The impression I got is that they made all kinds of compromises to make a program that would run in a small amount of memory but really needed much more - IOW, designing for the future at the cost of the present - and this is the main reason Word 6 got such a reputation as a slow, bloated resource hog. (Not that there weren't other reasons people hated Word 6.) So that's the other corollary to my thesis - it's all very well and good to talk about laptops with banks of removable flash memory as their main storage, but when designing a system for release Today, you need to make it run well on Today's systems. I don't expect Leopard to run well on a 500mhz TiBook, but it should run decently on systems a couple of generations old and run like lightning on everything being sold today. Likewise, if ZFS is planned for Leopard's successor, it should absolutely run well on everything being sold today - not just run like lightning on whatever systems are being sold in ~two years.Travis Butlerhttps://www.blogger.com/profile/04294490598103389900noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-78601313980302834222007-10-10T17:10:00.000-04:002007-10-10T17:10:00.000-04:00If HFS+ is truly case insensitive, then why is is ...If HFS+ is truly case insensitive, then why is is possible to create one file named "Straße" and one file named "STRASSE" in the same folder? Shouldn't these two names refer to the same file?<BR/><BR/>Case insensitive filenames just create more confusion in non-english speaking places.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-18108162221401699152007-10-10T14:00:00.000-04:002007-10-10T14:00:00.000-04:00Anton - I searched for the bug in question and got...Anton - I searched for the bug in question and got six hits.<BR/><BR/>6458218 - Fixed<BR/>2148249 - Fixed<BR/>6527325 - Fixed<BR/>6260386 - Closed<BR/>6181791 - Closed<BR/>6537415 - Closed<BR/><BR/>So I'm not sure I understand your post.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-80868938755015917912007-10-10T12:46:00.000-04:002007-10-10T12:46:00.000-04:00"Another probable show-stopper is that you can't r..."Another probable show-stopper is that you can't remove a disk from ZFS (yet). If you accidentally type the wrong command ("zpool add"), your USB disk attached to your laptop instantly becomes a dongle without which you can't boot your machine."<BR/><BR/>Did anyone else read this and imagine doing this on purpose? If your laptop won't boot without the USB dongle on your keychain, you have instant, cheap data security in case of theft.<BR/><BR/>Just sayin'.James Robinsonhttps://www.blogger.com/profile/07209475885330552071noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-80231392084402898782007-10-10T01:53:00.000-04:002007-10-10T01:53:00.000-04:00Derek Moor wrote:>You're right, ZFS does not have ...Derek Moor wrote:<BR/>>You're right, ZFS does not have a fsck tool. Because<BR/>>it doesn't need one. The ZFS repair model is to <BR/>>repair the storage pool online. <BR/><BR/>Actually, the current ZFS repair model is to reformat your pool and reload from backup.<BR/><BR/>Search for bug 6458218, for instance, on the OpenSolaris site, or search for 'assertion failed' on the zfs-discuss forum....<BR/><BR/>-- AntonAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-26623090106443863412007-10-09T19:49:00.000-04:002007-10-09T19:49:00.000-04:00I find MWJ's analysis on this to be of very poor q...I find MWJ's analysis on this to be of very poor quality. They wrote a terse and very snide piece with a bunch of incorrect info. They wrote a much longer response when Drew criticized them, yet they still are posting really bad data:<BR/><BR/>They go into a ton of minutiae about things like fatzap, without understanding how it fully works. That is below the level of detail necessary for the discussion.<BR/><BR/>They keep asserting that checksums on single drive configs are worthless. They are not. A year ago a had a drive error and lost a block of my btree which ruined a whole HFS partition. On ZFS any blocks can be ditto'ed so that even a single drive there are two copies. By default volume data is. That may not save a particular file, but it would probably save quite a few whole partition failures. Even without ditto blocks just knowing if that data is good or not has value.<BR/><BR/>They totally misconstrued Drew's points about the size of data and growth over time.<BR/><BR/>They keep asserting that somehow HFS+ is a lot more modern than it is. The HFS+ implementation is Mac OS X is nothing short of phenomenal. But HFS+ really is an extension to HFS. HFS had some hard coded limits based on the size of its data structures, so Apple increased the size of them creating an incompatible on disk format change. At the same time they made some other changes that they felt were good. But fundamentally the structure is the same as HFS was back when it was first implemented. They are so similar that HFS and HFS+ can be handled by the same FS module in the kernel. The basic design is over 20 years old. It is very good for what it is, but there are a number of things it just cannot do without incompatible format changes and a lot of work. Things which ZFS already does.<BR/><BR/>I also used to work for Apple (performance tuning and mobility work). I am not a storage expert, but I have a very good grasp of various filesystem behaviors as they relate to disk IO and drive throughput. While I absolutely think ZFS currently has some issues that make inappropriate for a default FS at this time, the analysis MWJ has presented publicly is so unprofessional as to be laughable.Louis Gerbarghttps://www.blogger.com/profile/03717315235496357757noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-43802713978681855802007-10-09T15:51:00.000-04:002007-10-09T15:51:00.000-04:00Alnisa: You're hitting several problems at once: d...<B>Alnisa</B>: You're hitting several problems at once: data corruption and the "big floppy" storage model. I'll make sure I cover both in my next post responding to MWJ's response.<BR/><BR/><B>Anonymous</B>: Yes, ARC should absolutely go into the UBC too. I'm actually not quite clear on the fundamental reasons why the ZFS cache is so closely interwoven — perhaps its internal-consistency logic, perhaps it lets it be smarter about caching hot data uncompressed, and leaving cool data compressed. Jeff, if you're reading this, that would make a nice blog entry.<BR/><BR/><B>LKM</B>: Frontend != backend. The frontend snapshot metaphor that the Time Machine UI uses could easily be upgraded to merge two backend data sources: ZFS snapshots and TM's own backups. <BR/><BR/><B>Anton</B>: There are definitely show-stoppers that keep it from being shipped right now, today. But zpool remove is going to show up, booting is going to happen, performance is being improved further. Like Derek said, in any filesystem panics are used to indicate a bug that needs fixing. Consistency is not a problem, modulo bugs: the chained checksums literally validate the entire tree. (Something you don't get with HFS+, btw.) Fuzzing attacks which create invalid data structures with valid checksums — which includes buggy external implementations that might corrupt portable drives — probably fall under the category of "mild to serious bugs" if they are handled with a panic instead of failing gracefully. They aren't necessarily showstoppers, though, since it's not particularly different from the status quo on Mac OS X today.Drew Thalerhttps://www.blogger.com/profile/01081923007415869973noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-54288324810420427742007-10-09T13:27:00.000-04:002007-10-09T13:27:00.000-04:00One of the coolest capabilities of ZFS is the abil...One of the coolest capabilities of ZFS is the ability not only to roll back state, but to save it and restore it. I blogged about it today at http://blogs.sun.com/openroad/entry/<BR/>zfs_and_file_system_stateDavid Goldsmithhttps://www.blogger.com/profile/00832320946591725014noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-90553054679694557982007-10-09T13:24:00.000-04:002007-10-09T13:24:00.000-04:00This comment has been removed by the author.David Goldsmithhttps://www.blogger.com/profile/00832320946591725014noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-50366568729524537052007-10-09T08:30:00.000-04:002007-10-09T08:30:00.000-04:00Re: Anton - You're right, ZFS does not have a fsck...Re: Anton - <BR/><BR/>You're right, ZFS does not have a fsck tool. Because it doesn't need one. The ZFS repair model is to repair the storage pool online. <BR/><BR/>ZFS stores redundant copies of its data structures. The uberblock is replicated four times (well, actually, the current uberblock is replicated four times, and there are four copies of previous uberblocks as well). Directory and file inodes are replicated as well. If ZFS encounters a corrupted inode, it will retry using a different copy; it will not simply panic.<BR/><BR/>Now having said that, yes, there are some cases where ZFS still panics. Those are bugs and are being worked on by Sun. ZFS is still a young filesystem (not even Sun uses it as the default fs for Solaris).Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-30026897997881544352007-10-09T03:23:00.000-04:002007-10-09T03:23:00.000-04:00Hi. I'm another storage & file system weenie, havi...Hi. I'm another storage & file system weenie, having worked on SCSI, RAID, FibreChannel & FireWire at Adaptec, UFS and QFS at Sun, and currently on a distributed file system.<BR/><BR/>I think the MWJ article is actually quite good, and covers a number of reasons why Apple can't readily adopt ZFS now, or without major changes.<BR/><BR/>ZFS has some good ideas; being able to check data integrity, for one. There are also advantages in bringing the file system and volume manager closer together, though I personally believe ZFS goes a bit too far here.<BR/><BR/>That said, ZFS has some limitations. One of the key points, and one which is likely to be a show-stopper for Apple, is that it does not have a file system checker. If its data structures are damaged, it simply panics. If you have one damaged block on your disk, or you encounter a bug which writes out a single bad byte, the whole disk may well become unreadable.<BR/><BR/>Another probable show-stopper is that you can't remove a disk from ZFS (yet). If you accidentally type the wrong command ("zpool add"), your USB disk attached to your laptop instantly becomes a dongle without which you can't boot your machine.<BR/><BR/>I believe Matt may well be correct about the overhead of ZFS vs. HFS on small files, but it may not be substantial in terms of storage space. An HFS+ catalog record is small compared to a ZFS dnode. More important, the copy-on-write nature of ZFS means that a simple 'touch' on an empty file on a ZFS file system on Solaris can result in 100+ I/O operations -- and in effectively random order on the disk.<BR/><BR/>Incidentally, ZFS has even worse overhead when it comes to extended attributes. It inherited a design from Solaris UFS which presents extended attributes as whole files, in a hidden directory per file! Imagine that each time the Finder wanted to look up the file type of a file, or Spotlight wanted to see comments, it had to do open, read, close for each attribute. This works for the NTFS "named streams" model, but that's fundamentally different from an "extended attribute" model. Luckily (?), few parts of Mac OS X use extended attributes today....<BR/><BR/>ZFS does not perform well (at present) in certain environments which require streaming read/write performance. This is partly because it's not extent-based and it doesn't try to write sequentially. Its maximum block size at present is 128KB, which means that in a 5-disk array, it writes only 32KB per I/O to each disk. This results in HUGE overhead on the storage side....<BR/><BR/>CPU performance, too, is an issue for file systems. It's easy to say that CPUs are getting faster than disk; but it's not always a good tradeoff to simply use more CPU to try and reduce disk I/O. If your CPU is actually busy -- and we're getting better at writing applications which can overlap I/O with computation -- then using extra CPU in the file system is not a good idea. There are a lot of important applications (think of video processing) in which CPU is the bottleneck, rather than I/O.<BR/><BR/>Two minor issues with comments --<BR/><BR/>1) The oft-quoted CERN report indicates that the particular hardware they were studying is actually using very cheap hard drives, and that most of the problems they ran into were related to bugs in those drives' firmware. One could argue that anyone could run into this, but I happen to know that Apple, for one, does intensive qualification of the drives they include in their systems. (At least they did a few years ago. Hopefully they haven't stopped in the name of saving money.)<BR/><BR/>2) Case-insensitivity is not in ZFS yet. The reference to Sun's ARC indicates that a project has been approved, but doesn't say anything about its current state, or even whether it's been halted.<BR/><BR/>There are some great ideas in HFS+ and some great ideas in ZFS. (And there are some in QFS and the many other file systems out there, too.) We'll never have the "one true file system" because there are greatly differing I/O needs. I'm sure that Apple will be evaluating ZFS for its locally-attached storage needs, and perhaps one day we'll see a change from HFS+; but it certainly won't be to ZFS as it stands today.<BR/><BR/>In my opinion, of course. ;-)<BR/><BR/>-- AntonAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-91267588404893161252007-10-09T03:00:00.000-04:002007-10-09T03:00:00.000-04:00@Drew Thaler: UI metaphor != implementation. While...@Drew Thaler: UI metaphor != implementation. While Time Machine looks similar to ZFS's snapshots, it's actually something very different. As I've said, one is a local state, the other one is backup.LKMhttps://www.blogger.com/profile/14534528035599262542noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-15075581131446524772007-10-09T01:15:00.000-04:002007-10-09T01:15:00.000-04:00Also, horror of horrors, there are all of those UN...Also, horror of horrors, there are all of those UNIX/X11 apps out there that run on Mac OS X and don’t use the Mac OS X Save dialog.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-35076266029958561582007-10-08T23:03:00.000-04:002007-10-08T23:03:00.000-04:00@ the "who doesn't use the Apple Save Dialog" crow...@ the "who doesn't use the Apple Save Dialog" crowd<BR/><BR/>Seriously? I have no less than a dozen programs in my dock right now that do not use the standard Apple save dialog including (as mentioned by others) nearly all Adobe software.<BR/><BR/>@ the "But your aunt might confuse file.txt and file .txt too" crowd<BR/><BR/>Umm, so? Aside from being a classic logical fallacy, are you really arguing that if you can't come up with a 100%, completely infallible solution, then you should try to make things easier for the user?<BR/><BR/>Also, there's a key difference there. R and r are THE SAME LETTER. They may not be to a computer or typographers, but in the minds of the vast majority of people they are the same thing.<BR/><BR/>But let's flip it around. What exactly is so beneficial about case-sensitivity aside from performance (which, as the original article states, is plentiful).Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-79184593558341033912007-10-08T22:57:00.000-04:002007-10-08T22:57:00.000-04:00This comment has been removed by the author.Travis Butlerhttps://www.blogger.com/profile/04294490598103389900noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-58435754145151927042007-10-08T16:23:00.000-04:002007-10-08T16:23:00.000-04:00Drew,ZFS uses a smarter cache eviction algorithm t...Drew,<BR/><BR/><I>ZFS uses a smarter cache eviction algorithm than OSX's UBC, which lets it deal well with data that is streamed and only read once.</I><BR/><BR/>This algorithm could (and probably should) be integrated into the OSX UBC, where it will benefit all filesystems, not just ZFS.<BR/><BR/>That is actually one of the few problems I have with ZFS: it sets off my layering violation radar. It's so much more than just a filesystem. I don't know how much of that integration is necessary to deliver the ambitious feature set, but I'd feel more comfortable if some effort was put into splitting out the buffer cache, LVM, etc. from the actual FS code.<BR/><BR/><I>When you are writing code that will last a decade or more, you need to think about tomorrow's problems and start solving them right now.</I><BR/><BR/>I couldn't agree more with this, and on that basis I'm happy to see Apple working on incorporating ZFS.<BR/><BR/>I think some of the backlash against the ZFS stories is a reaction to the breathless hype from people who saw it showing up in early Leopard seeds and immediately started talking about how ZFS cures cancer, etc., and leapt to the conclusion that it'd be the default Leopard FS. My favorite was all the stuff claiming ZFS would be necessary to do Time Machine.<BR/><BR/>The current AppleInsider story still has some of that feel; they're way overselling the prospect of ZFS becoming useful to end users in the short to mid term.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-26386994896692331182007-10-08T13:41:00.000-04:002007-10-08T13:41:00.000-04:00You mention that ZFS solves the huge storage space...You mention that ZFS solves the huge storage space issues, say like backing up a terabyte of data. I'm wondering if you could provide more detail. Mostly, I'm interested, because I tend to run into this problem all the time. My laptop has a 100GB hard drive, and I have 2 500GB FireWire/USB2 drives, 4 250GB FireWire, and then some random 100/150GB drives.<BR/><BR/>For a while now, I've been trying to transfer data from my 250GB drive that contained music to one of my 500GB drives, and the process has been horrible. I can't let it run overnight, because it stops as soon as it hits an error. And I don't have time to run it during the day, due to client calls etc. <BR/><BR/>So now my music collection is split across two drives, with repeats, etc.; and the same thing happens with my back-up files for clients—but its not as important to me that they remain unique.<BR/><BR/>For myself, I just see this getting worse and worse. I now purchase most of my TV Shows through iTunes, at a savings from my former $90/mo cable bill, but at a cost of storage space. So between music, tv, large database and graphic files, plus my User's folder. I'm already over a 1TB storage and growing, and I find it a pain just to transfer files, not to mention back-up.Unknownhttps://www.blogger.com/profile/09640870307940990303noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-83120428342346599972007-10-08T11:51:00.000-04:002007-10-08T11:51:00.000-04:00Jens: Okay, three places.Zach: Haven't used Deep F...<B>Jens</B>: Okay, three places.<BR/><B>Zach</B>: Haven't used <A HREF="http://www.faronics.com/html/DFMac.asp" REL="nofollow">Deep Freeze</A>, but my first guess is that they create a virtual <A HREF="http://developer.apple.com/documentation/Darwin/Reference/IOKit/IOBlockStorageDriver/Classes/IOBlockStorageDriver/index.html" REL="nofollow">IOBlockStorageDriver</A> and redirect writes elsewhere so that they can be flushed. It sounds like a snapshot, but not as flexible or automatic as ZFS. <BR/><B>LKM</B>: You're right. However, the subheadline 'it's fantastic, but not for macs as a "default" anything' doesn't inspire confidence in me.<BR/><B>Emanuele and LKM</B>: Time Machine uses a snapshot metaphor for its backups. Snapshots fit the same metaphor nicely.<BR/><BR/>Regarding case-insensitivity: Mike Ash summed it up best, I think. Taking it out of the bottommost layers of the storage stack doesn't change anything for users or developers, because apps need to work correctly in case-sensitive environments like HFSX anyway. I promise I will write up a separate blog post with more details since this comment thread is getting out of control.<BR/><BR/>Regarding laptops: <I>The future doesn't need to be like the past.</I> Just because notebooks have been single-drive machines doesn't mean they need to stay that way. What if the next laptop had an array of four or more 64GB flash sticks? With HFS+ they'd need to be wrapped up and presented as a single disk, meaning that if one dies the whole thing dies. With ZFS they could be managed as a pool — a lot more like RAM is. Your laptop would be thinner, more shock-resistant, and way easier to upgrade.Drew Thalerhttps://www.blogger.com/profile/01081923007415869973noreply@blogger.comtag:blogger.com,1999:blog-7898615.post-52410563464860252272007-10-08T08:45:00.000-04:002007-10-08T08:45:00.000-04:00We speak and write in a case-sensitive language, t...<I>We speak and write in a case-sensitive language, texters and slackers aside.</I><BR/><BR/>Uhm, no we don't. <BR/><BR/>Spoken language predates written language. And even then, the older written languages have no concept of case. It's not possible to convey case via spoken language. Hell, a lot of people can't even spell correctly.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-61649255508193467662007-10-08T06:47:00.000-04:002007-10-08T06:47:00.000-04:00...as for the case sensitivity issue: Apple has th......as for the case sensitivity issue: Apple has this right - preserve case, but ignore it. The simple answer as to why this is correct is that otherwise you could have (by my calculations) 512 DIFFERENT files all called 'readme.txt'<BR/><BR/>Can you imagine saving over a file, but miscapitalising a character ? Now you have a new file. Can you now imagine telling someone to open 'readme.txt' - which one ? ! <BR/><BR/>...and that's just for a file with a 6 character name and a TLA. A more realistic file name such as 'My geography homework assignment 08/10/07.doc' has something like 4,294,967,296 different capitalisations.....Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7898615.post-32854746543881473002007-10-08T06:34:00.000-04:002007-10-08T06:34:00.000-04:00I haven't picked up an much - or any - negativity ...I haven't picked up an much - or any - negativity regarding ZFS in the Mac community. In fact, the opposite is true - lots of people (me included) were getting very excited that this could be available in 10.5.<BR/><BR/>It seems pretty clear to me that ZFS is the way forward - it's only a matter of time. Just the ability to drop in a new disk and have it add capacity to the storage pool, instead of at a specific mount point, will be of massive benefit to almost all users.<BR/><BR/> I only hope that the apparent self-destruction of Sun doesn't mean that great developments such as ZFS will no longer come about.Anonymousnoreply@blogger.com