Sorry i can not because i use no more XFS, now i use EXT4 over Linux Software Raid0 over three HDDs... no more XFS, also i have updated to last Ubuntu
2010/8/13 Fabio Marconi <marconifa...@hotmail.it> > Hello Luis Lumbreras Picazo > > Can you please attach here these files: > > /var/log/syslog > /var/log/dmesg > /var/log/kern.log > /var/log/boot.log > > Thanks > > :)Fabio > > ** Package changed: ubuntu => linux (Ubuntu) > > -- > XFS incompatible with RAID0: Information get corrupted when Reading and > Writting on Raid0 XFS partition over (N-1)*StripeSize [Only writes to N-1 > stripes ovelaping info when writting to block over (N-1)*Size/N, also one > stripe is not used at read time] > https://bugs.launchpad.net/bugs/391975 > You received this bug notification because you are a direct subscriber > of the bug. > > Status in “linux” package in Ubuntu: Incomplete > > Bug description: > UPDATED: Fail localized more specifically -> when writing / reading from > Raid0 when XFS partition format. > At read time one stripe is not used (maybe last?), so when you write to a > block over (N-1)*Size/N the information on partition get corrupted, what i > have not checked is where the info writted really goes, i think it also does > not write on last stripe and info is overlaped, because with some little > writes a los of directories, structure is corrupted. > > Since what i could see when only write to a block number lower than > (N-1)*Size/N the information on partition do not get corrupted and can be > read after correctly, but when write to a block number higher than > (N-1)*Size/N the information on partition get corrupted, directory structure > also get corrupted. > > Also reads seems to read only from N-1 stripes, because speed is always > (N-1)/N when XFS over Raid0, but with EXT2/3/4 over same exact Raid0 the > speed is very near to N/N. I mean if used N stripes, speed is > N*SpeedOfStripe when EXT2/3/4, but with XFS it is (N-1)*SpeedOfStripe and > since zcav reads at block level the partition format must not affect read > speed because read is not at partition format level, it is at block level. > > Hope now is all clear. Have in mind whart i have done to ensure this: > Install one and another ... times Ubuntu ... One per each > test*configuration, too many hours, this night i have not dream just to make > this checks... But if there is needed anything else... just ask me for them, > ok? > > Now i also have been able to reproduce such on VirtualBox it would take > less time to make more tests, since i can install Ubuntu, while checking on > another Virtual... > > I have checked this with the next configurations (first three on real > hardware, next on VirtualBOX): > > Two stripes: > /dev/sda1 -> For Raid0 > /dev/sdb1 -> For Raid0 > /dev/md0 -> Composed of /dev/sda1 and /dev/sdb1, formatted as XFS > RESULT of zcav -> Read speed is 1/2 of what must be, and 1/2 of what is if > formatted as EXT4 > > Three stripes: > /dev/sda1 -> For Raid0 > /dev/sdb1 -> For Raid0 > /dev/sdc1 -> For Raid0 > /dev/md0 -> Composed of /dev/sda1, /dev/sdb1 and /dev/sdc1, formatted as > XFS > RESULT of zcav -> Read speed is 2/3 of what must be, and 2/3 of what is if > formatted as EXT4 > > Four stripes: > /dev/sda1 -> For Raid0 > /dev/sdb1 -> For Raid0 > /dev/sdc1 -> For Raid0 > /dev/sdd1 -> For Raid0 > /dev/md0 -> Composed of /dev/sda1, /dev/sdb1, /dev/sdc1 and /dev/sdd1, > formatted as XFS > RESULT of zcav -> Read speed is 3/4 of what must be, and 3/4 of what is if > formatted as EXT4 > > This next ones only checked on VirtulBox: > Five Stripes: Same idea, add /dev/sde1 to /dev/md0 with RESULT of zcav -> > Read speed is 4/5 ... > Six Stripes: Same idea, add /dev/sdf1 to /dev/md0 with RESULT of zcav -> > Read speed is 5/6 ... > Seven Stripes: Same idea, add /dev/sdg1 to /dev/md0 with RESULT of zcav -> > Read speed is 6/7 ... > Eight Stripes: Same idea, add /dev/sdh1 to /dev/md0 with RESULT of zcav -> > Read speed is 7/8 ... > Nine Stripes: Same idea, add /dev/sdi1 to /dev/md0 with RESULT of zcav -> > Read speed is 8/9 ... > Ten Stripes: Same idea, add /dev/sdj1 to /dev/md0 with RESULT of zcav -> > Read speed is 9/10 ... > ..etc.. > Up to 33 stripes (maximun i can with VirtualBox). > > In all cases it worked perfectly until a write on blocks with number higher > to (N-1)*StripesSize, all writes to blocks with number higher to > (N-1)*StripesSize makes the partition get corrupted. > > ------------------------------------------------------ > ----- I let below, the old text (with some little corrections just to > correct missmatchs), so can be seen a little history how i got to this > problem and so what have i check. --- > ------------------------------------------------------ > > I will try to explain as much detail as i can the BUG, because it is very > critical, makes you to loose all data while working and do not let to > recover anything, neither to reinstall without deleting all partitions on > all HDDs. > > So, sorry me if this is a long text and if i repeat somethings, my > intention is let as most clear as possible why it is Very Critical and how > easy and severe is and how to be able to reproduce it > > All times i tried with XFS i got a non working OS when updating pakages. > > I mean: When updating packeges an error occurs and icons on desktop > disappear, also bars icons changes, wallpaper disapear ... not able to open > a new console, ... data on hdd and memory get corrupted and after reboot, > obviously the system can not boot, system partition get totaly corrupted and > unrecoverable. > > This error only happens (only tested with XFS and EXT4 by now) if the > partition is XFS over Raid0, not if it is EXT4; rest types (EXT3, EXT2, > ReiserFX, JFS, ... not tested, since with EXT4 worked fine and i did not > have time to test). > > Let me try to explain how i have partitioned three HDDs (do not ask me why, > i have my reasons and security for data is nor importat, i make external > BackUPs of what i consider important, internal HDDs are only for OS and > temporal data, so speed is top most important, more because i use huge file > proccesing, fils bigger than 25GB each, and a lot of them): > > So this is how i partition my HDDs just to get the top most speed on boot > and work, while having System separated from my PersonalDATA (all temporal, > permanent data i store it on at least three different external usb hdds, > "BackUPs"): > /dev/sda: > /dev/sda1 -> Radi0 stripe 0 for / > /dev/sda2 -> Raid0 stripe 0 for /media/PersonalDATA > > /dev/sdb: > /dev/sdb1 -> SWAP for SWAP > /dev/sdb2 -> Raid0 stripe 1 for / > /dev/sdb3 -> Raid0 stripe 1 for /media/PersonalDATA > > /dev/sdc: > /dev/sdc1 -> ext3 for /boot > /dev/sdc2 -> SWAP for SWAP > /dev/sdc3 -> Raid0 stripe 2 for / > /dev/sdc4 -> Raid0 stripe 2 for /media/PersonalDATA > > /dev/md0: Composed of /dev/sda1, /dev/sdb2 and /dev/sdc3 and formated as > XFS, mount point / > /dev/md1: Composed of /dev/sda2, /dev/sdb3 and /dev/sdc4 and formated as > EXT3, mount point /media/PersonalDATA > > Sizes of partitions are as follows: /boot of 512MB, / of 24GB and SWAPs as > big as needed just to equal size for /media/PersonalDATA on all three HDDs, > the rest. > > Let me put an example how i calculate sizes on for example PATA HDD near > 80GB, SATA HDDs 81GB so: > /boot -> 512MB on SATA > / -> 24GB striped along all three HDDs (Raid0) > two SWAP partitions, one on each SATA > PATA one 80GB - 24/3 -> 72GB, so size for /media/PersonalDATA is 72GB * 3 = > 216GB > One SATA 81GB - 512MB -> 80.5GB; 80.5GB - 24/3 -> 72.5GB; 72.5GB - 72GB -> > 0.5 for SWAP > Other SATA 81GB - 0MB -> 81GB; 81GB - 24/3 -> 73GB; 73GB - 72GB -> 1GB for > SWAP > Result: > /boot -> 512MB > SWAP1 -> 512MB > SWAP2 -> 1024MB > / -> 8GB*3 Raid0 -> 24GB > /media/PersonalDATA -> 72GB*3 Raid0 -> 216GB > > Each HDDs reports on zcav quite similar speeds, about 57MB/s on fast part > and 30MB/s on slower part > Note: zcav report near 57MB/s*3->171MB/s (Really about 155MB/S) when not > XFS is selected for partition > Note: zcav report much less than 57MB/s*3->171MB/s (Really about 102MB/S) > when XFS is selected for partition > I think this indicates a big an serious problem. > > With this configuration system install from CD ends correctly, reboot and > system works perfect. > > Since the error makes system unuseable any more and needed to reinstall > from scracth i think it is a serious problem with XFS. > > WRONG -> Extra: On another machine with only two HDDs it works perfect > Raid0 with XFS for system gives no problem (till now, hopes it will not give > problems on future, but who knows?). > RIGHT -> Extra: On another machine with only two HDDs it works perfect > Raid0 with XFS for system gives no problem (till now, hopes it will not give > problems on future, but who knows?), also get corrupted in same manner, it > seemed to work fine because stripe size was bigger so problem occurs when > more files where added, so a write to a block higher to (N-1)*StripeSize, > since N=2, when write to the upper half of partition size. > > WRONG -> If i use Three HDDs it is unuseable, all times error occur when > updating packages, why? i don't know. > It is reproductable 100% on all PCs i have tested. > > RIGHT -> If i use Three HDDs it is unuseable, all times error occur when > updating packages, why? because stripe size is so small that updating > packages makes writes to last N stripe, so partition get corrupted. > It is reproductable 100% on all PCs i have tested, also on Virtual ones > under VirtualBOX. > > Let me explain how to reproduce this (allmost on three PCs i have tested it > for four times on each and also on virtualBOX with a result of 100% of times > the error becomes and system stop working ata same point, installing > packages updates): > > Steps fllowed to reproduce it (quite WRONG, the RIGHT will be, make stripes > sizes small enought, so last must be used): > -Have a PC with on PATA HDD and three SATA HDDs of quite similar size > -Delete all partitions on all (Three) HDDs [One PATA, Two SATA] > -Create on PATA (/dev/sda) the next partitions: One for Raid0 for / > (/dev/sda1) and another for Raid0 for /media/PersonalDATA (/dev/sda2) > -Create on SATA (/dev/sdb) the next partitions: One for SWAP (/dev/sdb1), > another for Raid0 for / (/dev/sdb2) and another for Raid0 for > /media/PersonalDATA (/dev/sdb3) > -Create on SATA (/dev/sdc) the next partitions: One for /boot (/dev/sdc1), > another for SWAP (/dev/sdc2), another for Raid0 for / (/dev/sdc3) and > another for Raid0 for /media/PersonalDATA (/dev/sdc4) > -Create a Raid0 (/dev/md0) with /dev/sda1, /dev/sdb2 and /dev/sdc3 [for /] > -Create a Raid0 (/dev/md1) with /dev/sda2, /dev/sdb3 and /dev/sdc4 [for > /media/PersonalDATA] > -Format /dev/md0 as XFS (that will cause problems after end installation, > but if selected EXT4 no problem will be caused), mount point as / > -Format /dev/md1 as EXT3, mount point as /media/PersonalDATA > -Format /dev/sdc1 as EXT3, mount point as /boot > -Format /dev/sdb1 as SWAP > -Format /dev/sdc2 as SWAP > -Install Ubuntu normally > > WRONG -> Installation ends without any problem, but now Update packages > window appear. > RIGHT -> Installation may end without any problem, but now Update packages > window appear if Stripe size is small enought; if stripe is also smaller, > also on installation corrupt occurs. > > WRONG -> Well if for / was selected XFS then Update packages will not end. > RIGHT -> It is not Update packages what was causing the problem, is XFS, it > get partition information corrupted when writing to blocks numbers higher > than (N-1)*StripeSize/BlockSize > > What happened to me, since i let three stripes of 8GB each was just after > downloading all packages, just at the begining of installing an error occurs > while writing to XFS and the system crashes: > -Icons on screen disapear, icons on bars changes, desktop wallpaper > disapear, etc... > -Trying to launch a console window fails, ... > -If rebooted, the system does not reboot any more, so only solution is > reinstalling from scratch again and again, until XFS for / is not selected > (till now i only tested with XFS and EXT4). > > And it is also worst, after the error: > If try to reinstall without previously reformating (deleting all > partitions), at partitioning point on install it does not let you to > continue because partitioning menus does not appear, you are forced to use > Ctrl+Alt+F2 (alternative console) and use fdisk to delete partitions, then > go back to install menus and tell it to redetect hard disk, only then it let > you continue specifing partitions, installing, etc ... > > I consider this BUG very Critital, because it gets you with a non > recoverable system, non bootable, non reinstallable and only solution after > this fail is deleting all partitions on all HDDs with fdisk on console and > not with install menus on screen. > > It seems to have a serious problem when writing to XFS over Raid0, while if > using EXT4 no problem seems to appear. > ADDED -> Problem occurs only when writing to blocks numbers higher than > (N-1)*StripeSize/BlockSize > > Now it becomes to me one question: > Would i need to re-install all other PCs that i have selected XFS for /? I > will answer to this question by myself: > Yes, of course, XFS is not reliable over Raid0, do not use XFS any more > never again over Raid0 until solved, but what else can be used? EXT4? Yes, > EXT4 is fast enought and works perfectly with Raid0, not only with two > stripes, also with three stripes. > Now, I do not need to test again speeds and select the top most fast except > XFS, the selected option is EXT4, this would take me more than a week of > intense test on some PCs, if anyone has done it...! Is there any reliable > comparative? Of course i mean such test done over a Three HDDs on Radi0 > configuration. > > Something one time i have been able to see is that the fail seems to occur > when writing to XFS over Raid0 when updating packages. > More, zcav report makes me think something is very wrong with XFS, because > read speed is 2/3 of what was supposed to be and if i use EXT4 instead of > XFS i get with zcav a read speed of 3/3. > > VERIFICATED: Seems like if with XFS it would only be really using two HDDs, > not all three, so any write corrupts data, but then why install works fine? > and why rebooting works fine?, maybe corrupt only becomes whe crossing 2/3 > of total partition size?, so on install all is written correctly and on > reboots most is read, writes are only for logs, etc.. so seems a fatal XFS > incompatibility with Raid0. > > Note: I do not want to be asked why i use Three HDDs for Raid0, that is up > to me and i have my reasons, let me expose just the top mot important for > me: > -I only have Two PATA channels and Two SATA channels. > -One PATA channel has a DVD-Writer > -The other PATA channel has a PATA HDD > -I have two SATA ports, each with one HDD > -So only Three HDDs can be at the same time working. (Except i put another > PCI controller that can not fit, no free PCI slots available) > -I need top most speed on procesing huge files (bigger than 25GB each) > So if i make a Raid0 only with two of them i get lower speeds, ... > Since Raid0 works perfect with EXT3 and EXT4 partitions format and gets > quite near full 3x speed, i configure Raid0 for using all Three HDDs. > > Why i do not use Raid5? Easy, i never let important files inside a PC, i > only let inside PCs files for OS and only while using it the temporal work, > so speed is much more important than data security. > For data security i have another Three external USB HDDs, each with a full > identical copy (BackUP), so if also two of them fails there is the third to > be able to restore, and i never have powered on all at threee at the same > time. > > Some important questions: > Why Raid0 (/dev/md0) fails if XFS format is selected?, and why only when > reinstalling packages? > ANSWER -> Because XFS writes on Raid0 corrupt information when writes to > blocks numbers higher than (N-1)*StripeSize/BlockSize > Also, why zcav report 2/3 of the speed that must supposed to be? > Also if instead of XFS i use EXT4, no problem and speed is 3/3. > > Tests done with zcav without changing partition scheme: > -Data report of zcav for /dev/md0 over a Three HDDs Raid0 when formatted as > XFS: 114MB/S > (57MB/s * 3 = 171MB/s, what is wrong, why speed is 2/3? 57MB/s * 2 = > 114MB/s ¡! Seems only to use two HDDs?) > -Data report of zcav for /dev/md0 over a Three HDDs Raid0 when formatted as > EXT4: 171MB/S > (57MB/s * 3 = 171MB/S, it is ok) > > Hope i could let it enought clear. > > P.D.: Sorry not to attach zcav reports, but now i am not near the PCs (tee > would let it, but i consider not much important) > > To unsubscribe from this bug, go to: > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/391975/+subscribe > -- XFS incompatible with RAID0: Information get corrupted when Reading and Writting on Raid0 XFS partition over (N-1)*StripeSize [Only writes to N-1 stripes ovelaping info when writting to block over (N-1)*Size/N, also one stripe is not used at read time] https://bugs.launchpad.net/bugs/391975 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
