On Tue, 6 Dec 2005, Nicolas Macquet wrote: > Hi there, > > Thanks for your answer Alan, I tried the 2.6.12-1.1376_FC3smp (technical > constraint, cannot update with newer) > > I have re-done my test with : > -6 USB disks : 4 on a HUB and the 2 others on a second HUB. > -simultaneous mkfs.ext2 commands directly in terminal. > -unplug of 2 disks while formating. > > Results are : > -much better handling of other devices which are formating. I mean : only > those which were unplugged failed to restablish correctly. Disks which were > not unplugged, have finished their formating successfully. > -the first unplugged disk blocked on formating process : 89/560 according to > terminal output. > -the second disk had an other behaviour : mkfs.ex2 was formating as if the > disk was still plugged and the inode table counter was increasing to the > limit and then, when it should create the directories, it exits with the > error code 160. > -first unplugged disk generated lots of kernel logs such as "bad sector", > "rejecting I/O dead device...". but as previously, kill of the mkfs process > or rmmod of usb modules or even rebooting commands failed. USB is no more > responding to plug/unplug of devices...
Part of what you see is unavoidable. The kernel doesn't do disk output right away; instead the data gets stored in buffers and sent to the disk later. The errors don't occur until the buffers actually get sent to the disk, which may be some time after you have unplugged the drive. The fact that the processes would hang and the USB stack stopped responding is caused by bugs in the kernel. These bugs have been fixed in 2.6.14. > maybe this behaviour is corrected in 2.6.14 or FC4 kernels but the target > machines are still deployed in production sites, therefore system upgrades > are very painfull ! I understand. :-( Eventually you will be able to upgrade, and then things should work better. For now, can you try upgrading just one machine simply as a test? Alan Stern ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
