> On Friday May 2, yusufg@outblaze.com wrote: > > Neil, Thanks for the info but I am kinda confused as to why the sudden > > writeout occurs at 4 minutes if the default ext3 settings is to flush > > the journal every 5 seconds. Do you know what the correlation between > > these times would be. > > I'm not sure. > There is a bug in some kernels where the time stamp of some blocks is > wrong, so old data doesn't get flushed out by bdflush when it should. > This can mean that data older than the bdflush interval stays in > memory until it is forced out by the journal being full. > > Maybe your average data rate fills the journal in about 4 minutes, and > the other bug is interfering with the regular bdflush writeout of data > blocks. > > What kernel are you running? Are you using any ext3 patches on top of > it? Neil, I think the bug you are referring to is fixed by akpm's introduction of jbd_refile_buffer in fs/jbd/transaction.c. Looking at the source for Redhat's kernel, I see that that is only fixed in the current rawhide kernel and as such all RH kernels from 7.3 till RH 9 would have this bug where buffers hang around longer than the bdflush kernel and then cause a write storm when the journal is full This seems to hurt busy servers a lot Maybe Stephen can comment on this more. I'll try to file a bugzilla report in case this helps to get an errata kernel released _______________________________________________ Ext3-users@redhat.com https://listman.redhat.com/mailman/listinfo/ext3-users
