On Mon, Apr 16, 2007 at 05:27:51PM +0200, Tomasz Kłoczko wrote: > On Mon, 16 Apr 2007, Adrian Bunk wrote: > >> On Mon, Apr 16, 2007 at 04:01:23PM +0200, Tomasz Kłoczko wrote: >>> ... >>> Few days ago I'm swich two backup servers with few TB storage from Linux >>> to >>> Solaris .. only because client want use ZFS .. because ZFS is EXCELENT >>> for >>> this kind tasks (only because it allow save many thousands of >>> <put_your_currency_name> because it allow better utilize the same >>> storage) >>> and trust me .. cases like this will be more .. much more and changing >>> licensing Linux code will be MUCH more easier than reinventing wheel >>> (wich >>> will be reimplemnting ZFS under GPL). >> >> This is a technical mailing list, so let's start with technical >> arguments: >> >> Why did this client want to use ZFS? > > Because switching to Solaris was chipper than buying next faster FC/SCSI > storage. Simple ? > >> Because his boss was convinced by a marketing guy that ZFS was the best >> invention since sliced bread? > > In this scenario ther is no place for "marketing guy" .. try again .. > (maybe it can occure in US or Germany but trust me .. not in Poland 8-) > >> Or due to technical limitations in what Linux currently offers >> resulting in ZFS bringing him direct advantages on these servers? > > Yes .. it is Linux limitiations because it is very hard to provide > simultanouse streams of backup data with threaded compression (using in > this case pbzip2) with good CPUs utilization because most streams waits on > I/Os and most of CPUs are not fully utilized. All this becase single stram > of compressed data can't be easy dinamically switched to another (not busy) > disk in JBOD. ZFS by two level allocation (on device and block level) will > not wait for finish I/O but will try use another/not busy device in ZFS > pool. This is *main* reason integrate in one layer VFS and LVM in case ZFS. > By integrate this two layers you can make deciion where data will be > written depending on *current* devices utilization. In all other "classic" > ways you will break layered OS model .. so in ZFS case conclution like "we > must integrate this two layers in one" it is not bug but feacture and was > FUNDAMENTAL.
You are having IO problems doing bzip2 ??? This sounds as if your application is doing something silly like e.g. using O_DIRECT or you are mounting your filesystems with "-o sync". On my 1.8 GHz Athlon, it takes 2.5 minutes to compress a 250 MB kernel tar to 40 MB - and this is with the data cached in RAM, so no IO involved. That's 1.7 MB/s resp. 0.3 MB/s. I'm even having problems to imagine IO problems with 4 or 8 CPU machines doing parallel bzip2 to a single disk - with any filesystem. > This is not all .. backup data must be safe in best possible form .. in > time .. and it mean in this case that checksumming is NECCESSARY. Look .. > ext4 for now only have plans for implemting checksuming > (http://www.bullopensource.org/ext4/files/ext4.txt) and ATM on Linux there > is no FS with this kind abilities .. so yes again: this was Linux technical > limitation. bzip2 already checksums all data, so why do you need a second checksum at the filesystem level for your backups? >>> Problem is not on technical area but on licensing and it is plain Linux >>> word problem because neccessary in this case changes on CDDL side will >>> make >>> this code less oppended than now .. so you can (probably ?) forget about >>> GPLing ZFS code (and ZFS it is not all what will good to have from Sol in >>> Linux). >>> IMO current Linux licensing less is importand than bringing in possible >>> simpler way things like ZFS to Linux. So best/simpler way will be start >>> change Linux licensing for save all GPL goodies and allow interract with >>> code on license like CDDL. >>> >>> Licensing is for allow keep in best possible form Linux. If it can't do >>> this in best possible way it must be change (must evolve .. like many >>> othes >>> things around). >> >> There are at about 10.000 people who contributed to the Linux kernel, >> some of them unreachable or even dead. > > Do you know who was Paracelsus ? He was medic hundriet years ago. They > discover and verbalise some kind fundamental (?) law for medicine which can > be used not only on medicine area. He sayd "kills not subtance but dose of > substance". So anything can kill you/animal/project .. you can kill someon > also using oxigen (not only low level of oxigen kills but also to much can > kill). Try to think on how this law on how many diffret ways can be > trasformed/appied to this kind of arguments. Look on how many developers > migrate to another unices in last few years (count only two for simplicity > like Solaris and MOX). Try looking for public forums statistics for example > Linux vs. Solaris and after this try to answer on "is it 10k is it realy > big number in this case or not ?" (IIRC google provides very good tools for > anyone who want this kind answers). I don't need Google for this. It's easy to extract from git that patches that were applied to the Linux kernel during the last 2 years contained 3196 unique Signed-off-by: lines. Some people might have lines with different email addresses, but this still makes > 2000 contributors during the last 2 years alone. Plus all the other people who contributed during the first 14 years of Linux kernel development but didn't during the last 2 years. You could argue whether there were really 10.000 people or "only" 5.000 people who contributed code to the Linux kernel, but that doesn't make a real difference. > kloczek cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
