Hello! Pavel! Awesome!
Please add one killer feature about ZFS - compete support for SSD with TRIM and not-killing-this-sector-by-thousands-writes :) On Thu, Nov 13, 2014 at 11:17 PM, Pavel Snajdr <li...@snajpa.net> wrote: > Well, innovation isn't about matching features that someone else has > just for the sake of having them too, is it? :) > > What lot of people are missing about ZFS is that it is a self-contained > project trying to solve real storage problems. It's not trying to be a > filesystem. It is a complete storage solution. It's like you'd take a > NetApp and plugged it into your kernel directly. > > Example features of ZFS that BTRFS will never have due to this fact: > > - ARC - a smart caching mechanism, with which we're able to deliver > almost 100% hitrate almost 100% of the time - something that isn't even > remotely imaginable with linux LRU dcache > > - L2ARC - second level ARC enabling you to cache less used ARC entries > onto a SSD > > - dedicated device for ZIL - synchronous writes are a real pain with any > CoW filesystem, ZFS solves this so elegantly that it even beats Ext4 > there - you can have your sync writes sent to a fast SSD or a NVRAM > device. Thanks to this I don't even notice heavy MySQL instances on our > machines, until we run out of CPU power. The disks aren't the > show-stopper anymore > > - NFS, SMB, iSCSI integration - people judging ZFS from the traditional > linux kernel perspective don't get why should it be a filesystem's job > to do these - like I said, ZFS is not trying to be a filesystem. It's > trying to be the last storage solution you'll ever need on your server. > > Etc. I could go on about this a while :) > > Regarding the licensing issues. Well. ZFS isn't trying to be the best > filesystem for Linux. As far as I can remember, nobody from the ZFS > world has ever had any ambitions to get it into Linux. Even if the > license would allow merging ZFS in the kernel, the reality of ZFS design > as a self-contained solution wouldn't probably be accepted as well in > the Linux community as it was in FreeBSD. They're two completely > different cultures. > > As I've already mentioned FreeBSD, here comes the next advantage ZFS has > over anything that Linux provides - BTRFS included: you can take your > pool today and open it on another platform, be it Linux, FreeBSD or > Illumos. Work is being done to ensure these implementations don't drift > apart and stay compatible - it is know as the OpenZFS project. > > Regarding the patent issues, the same essentially goes for BTRFS, the > main concern wouldn't be Oracle here, it would be NetApp. They hold > enough patents to kick anyone around, doesn't matter if it's OpenZFS or > BTRFS. Only with Oracle they seem to be okay, because of Sun's previous > dealings with NetApp in this regard. > > However, these patent concerns doesn't seem to hold any ground, as you > can see Nexenta and Joyent both making reasonable enough success to > tickle NetApp's nerves (especially Nexenta since they're a direct > competitor of NetApp in some market segments), yet nobody is suing them. > This is even less of an issue for me as everything I operate is in > Europe, where software patents don't apply. > > Now it looks like I'm actually the one who's on holy crusade for ZFS here :) > > But it all started off with me being really, really disappointed with > Ext4 performance. With ZFS I can get 80-120 heavy LAMP stack containers > on a single node, whereas the disks would be long dead with Ext4 before > I would even reach a half of that. > > I've played around with having separate ext4 partitions for every CT (it > was before ploop), I've tried Facebook Flashcache to catch the sync > writes and offload them onto a SSD, I think I have tried everything I > could and not much has really changed since then on the Linux storage > scene (2012). > > There's BTRFS, which to a layman looks like it's almost in feature > parity with ZFS, but if you actually try to use it, then "WAT" comes out > of your mouth like every second word. It still needs a lot of work. > > Whereas ZFS as been in the production for more than 8 years now. And it > still is in active development with lots of companies and individuals > trying to make it better - they have much better starting point as far > as the innovations go, because they act on their own playground and they > don't have to deal with politics of such a huge project like Linux > kernel is. > > /snajpa > > On 11/13/2014 06:24 PM, Scott Dowdle wrote: >> Not really. That isn't to say that btrfs is done or that all of its >> features, especially those added much later in the development cycle, are >> stable. So, I don't contend that btrfs is a suitable contender to zfs at >> the moment but it does have a few benefits that will eventually put it over >> the top... past zfs on Linux. What are they? >> >> 1) It's in the mainline kernel and will be available in all distros with >> sufficiently new enough kernels. >> >> That's it. That's all it needs. Being part of mainline Linux means that >> it'll get better integration with system tools by the distros and hopefully >> OpenVZ at some point. ZoL will never get that... unless of course a Linux >> distro built just for ZoL comes along. >> >> Because of licensing issues, none of the major Linux distros will ever ship >> with ZoL pre-installed. Sure you can add it yourself... and it does a >> fairly good job of rebuilding itself when the kernel changes... but the >> extra work to add it and keep it updated will make it always be adopted less >> than something that is built-in. Kudos to the ZoL developers for creating >> such a solid product and making packages for many distros and making it as >> easy as possible to add. >> >> For those not wanting all of the more advanced features btrfs is ready >> now... and as I stated, SUSE and Oracle have been shipping it for some time. >> When Red Hat signs off on it, I think that'll raise its status a bit. For >> those just using it for checksums and CoW, it offers those advantages now. >> >> So far as a feature for feature comparison of zfs and btrfs there is >> probably a 95% feature overlap with btrfs having some features that zfs >> doesn't and vice versa. >> >> Do I blame anyone for using zfs? No. It's great. I just don't want to use >> it myself. The good thing is that is is very unlikely that Oracle will ever >> sue over patent issues... because they were the early sponsor of btrfs when >> most of the work was being done so they only have themselves to blame. > > _______________________________________________ > Users mailing list > Users@openvz.org > https://lists.openvz.org/mailman/listinfo/users -- Sincerely yours, Pavel Odintsov _______________________________________________ Users mailing list Users@openvz.org https://lists.openvz.org/mailman/listinfo/users
