W dniu 14 lutego 2011 20:47 użytkownik Eric Sandeen <sandeen@xxxxxxxxxx> napisał: > On 2/13/11 12:29 PM, Dennis Jacobfeuerborn wrote: >> On 02/12/2011 11:52 PM, Ric Wheeler wrote: >>> On 02/12/2011 05:31 PM, Michał Piotrowski wrote: >>>> Hi, >>>> >>>> W dniu 12 lutego 2011 23:19 użytkownik Ric Wheeler >>>> <rwheeler@xxxxxxxxxx> napisał: >>>>> On 02/12/2011 05:12 PM, Michał Piotrowski wrote: >>>>>> Hi, >>>>>> >>>>>> I added a disc to my box. I wanted to use ext4. I run fs_mark to test >>>>>> speed, to my surprise I heard a really strange noises. >>>>>> >>>>>> It's very strange because the drive is new >>>>>> 9 Power_On_Hours 0x0032 100 100 000 Old_age >>>>>> Always - 12 >>>>>> >>>>>> >>>>>> # fs_mark -d test/ >>>>>> [..] >>>>>> FSUse% Count Size Files/sec App Overhead >>>>>> 0 1000 51200 22.8 54347 >>>>>> >>>>>> I decided to create an ext3 file system on this drive and everything works >>>>>> fine. >>>>>> >>>>>> # fs_mark -d test/ >>>>>> [..] >>>>>> FSUse% Count Size Files/sec App Overhead >>>>>> 0 1000 51200 103.7 57229 >>>>>> >>>>>> When I mount this ext3 fs as ext4 and run fs_mark I hear strange sounds >>>>>> again. >>>>>> >>>>>> I use F14 and self compiled kernel from rawhide 2.6.37-1.fc14.x86_64 + >>>>>> e2fsprogs-1.41.14-2.fc14.x86_64. >>>>>> >>>>>> I mount ecryptfs on top of this file system. >>>>>> >>>>>> Does anyone know what might be causing this strange ext4 behavior? >>>>>> >>>>> Hi Michael, >>>>> >>>>> fs_mark run a fsync heavy test. What you might be hearing is the impact of >>>>> the fsync's. ext4 defaults to using "write barriers" enabled, ext3 does not. >>>>> Without write barriers, those fsync push data from the box to the write >>>>> cache on the drive only. With barriers, the disk will flush that cache to >>>>> the platter, so the platter moves and you probably hear the head, etc. >>>>> >>>>> You can test if this is the cause by mouting ext4 with "nobarrier" to see if >>>>> the noise goes away. >>>> I mounted fs with nobarrier and now it works just like ext3. Thanks! This solves >>>> the riddle :) >>>> >>> >>> Good to hear that it worked! >>> >>> Note that the barrier code makes your data safer, so you should run with it on >>> by default (unless you really don't care about the file system). >> >> If ext3 was running fine without barriers for all these years why is this >> such a problem with ext4? Does ext4 do something differently that barriers >> are now required? > > barriers are always required for integrity if you have a volatile write cache; > this is true for ext3 as well. You may not see problems on every power loss, > but eventually you will. > > The problems are often found after the fact, with a subsequent runtime or fsck > error, so the culprit may not be immediately obvious. What are the recommended "best practices" for mounting ext3/4 file system? For performance - noatime, for those who care about data integrity - "barrier=1,data=journal" or just "barrier=1" if we also care about performance. Am I missing something? > > -Eric > >> Regards, >> Dennis > > -- > devel mailing list > devel@xxxxxxxxxxxxxxxxxxxxxxx > https://admin.fedoraproject.org/mailman/listinfo/devel > -- Best regards, Michal http://eventhorizon.pl/ -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
