Hello, I have been debugging and struggling with the following problem: On 2.6.13-1.1532_FC4: 1. create a logical volume of size 10GB (the size does not matter, some size...) 2. create a snapshot for this logical volume (50% of the original) 3. Switch to another console window, and do dd if=/dev/zero of=/dev/vg_test/lv_test bs=1M that simply writes a lot of zero'd pages to the original volume, causing a lot of data written into a snapshot which is fine and expected. Now comes the problem. 4. Go to another console window, and do lvremove /dev/vg_test/lv_test_snap to remove the snapshot (WHILE the dd command is running!), say YES when asked to confirm and you will find that the system cannot remove the snapshot until all IO ends (most times). Let's continue this scenario 5. on another console window, do lvscan it hangs and is not able to enumerate all logical volumes (pressing ^C exists) 6. Go to another console windows, and do dd if=/dev/vg_test/lv_test of=/dev/null bs=1M and you will see that this process reads for a little while and then eventually all IO on /dev/vg_test/lv_test ceases and the system ends up being hung. This has occurred with various FC4 kernels (2.6.12, 2.6.13, 2.6.14) and after upgrading as recommended to device-mapper 1.02.02 (original: 1.01.02), lvm 2.02.01 (original 2.01.08) I find that I get kernel crashes. The following thread on google demonstrates the result which appears to have been around for a while: http://groups.google.com/group/linux.kernel/browse_thread/thread/6af10a7 680948714/d69cbfa7b18b63e6?lnk=st&q=client_free_pages&rnum=3#d69cbfa7b18 b63e6 I apologize for being lengthy and I would like to acknowledge the hard word everyone is putting into the open source community. I would like to hear from others who have experienced problems removing snapshots while the system is under heavy IO load. Is this a known issue? Is there a possible workaround? Thank you Steffen. _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
