I ported my zfsstress program over to btrfs, and started running it on a test machine a few weeks ago. See here for more information and a link to the program: http://www.tummy.com/journals/entries/jafo_20100418_124309 It looks like after around 8 days of running, there were some issues, as shown in dmesg (below). The system is a 64-bit Atom 330 with 2GB RAM, and a single 250GB hard drive. btrfs has 200GB of that. The OS is the Fedora 13 Beta with kernel 2.6.33.1-24.fc13.x86_64. I had started btrstress and let it run a day or so. Then I went in and deleted the subvolume that btrstress puts everything into, then started it again. A few days later, I did the same. I also tried turning on compression with "mount -o remount,compress /data". Around 6 hours later, it looks like btrstress was no longer working. The primary issue seems to be that file deletions aren't freeing up space. btrstress will fill the file-system up, but disables any write operations if the "df" output shows more than 95% full. So normally it would clear up some snapshots or files until it gets back down to 95% or less, and start doing writes again. However, after the Oops, it looks like it was able to continue allowing removes of files and snapshots, but "df" is no longer reflecting that. For example: [root@btrtest btrstress-lZ6C7txz3n]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda1 29G 13G 16G 45% / tmpfs 991M 0 991M 0% /dev/shm /dev/sda4 200G 189G 9.9G 96% /data [root@btrtest btrstress-lZ6C7txz3n]# find /data /data /data/btrstress-lZ6C7txz3n [root@btrtest btrstress-lZ6C7txz3n]# btrfs subvolume list /data ID 28423 top level 5 path btrstress-lZ6C7txz3n [root@btrtest btrstress-lZ6C7txz3n]# du -sh /data 4.0K /data [root@btrtest btrstress-lZ6C7txz3n]# I've left the test system as it is, let me know if there's anything you'd like me to try on the system before I wipe it and start again. Also, let me know if this sort of report helps. Note that after enabling compression, but before the oops, dmesg reported a bunch of messages like: btrfs: relocating block group 11840520192 flags 1 btrfs: relocating block group 10766778368 flags 1 btrfs: relocating block group 9693036544 flags 1 btrfs: relocating block group 8619294720 flags 1 btrfs: relocating block group 7545552896 flags 1 btrfs: relocating block group 6471811072 flags 1 Note that the group numbers started at 212630241280 and reduced by around a billion for every line. dmesg output of oops below. BUG: unable to handle kernel NULL pointer dereference at 0000000000000075 IP: [<ffffffff810e380f>] page_cache_sync_readahead+0x15/0x3a PGD 7a937067 PUD 3310c067 PMD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/pci0000:00/0000:00:1e.0/0000:04:00.1/irq CPU 0 Pid: 30242, comm: btrfs Not tainted 2.6.33.1-24.fc13.x86_64 #1 D945GCLF2/ RIP: 0010:[<ffffffff810e380f>] [<ffffffff810e380f>] page_cache_sync_readahead+0x15/0x3a RSP: 0018:ffff88003309fac8 EFLAGS: 00010206 RAX: 0000000000000000 RBX: ffff880046476940 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff88007ac840d0 RDI: ffff880046476b70 RBP: ffff88003309fac8 R08: 0000000000003f6a R09: 0000000000000246 R10: ffff88003309f8d8 R11: 0000000000000000 R12: ffff880077422968 R13: 0000000000000000 R14: ffff880046476608 R15: 0000000000000000 FS: 00007f893574d740(0000) GS:ffff880004a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000075 CR3: 0000000033004000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process btrfs (pid: 30242, threadinfo ffff88003309e000, task ffff8800777a8000) Stack: ffff88003309fb68 ffffffffa0364899 ffff88003309fae8 0000000181c00001 <0> ffff880046476a30 ffff880046476608 ffff88003309fb28 0000000000003f69 <0> 0000000000000000 ffff88007ac840d0 0000000000003f6a 0000000181c00000 Call Trace: [<ffffffffa0364899>] relocate_file_extent_cluster+0x18f/0x399 [btrfs] [<ffffffffa0364b46>] relocate_data_extent+0xa3/0xbb [btrfs] [<ffffffffa0364e1a>] relocate_block_group+0x2bc/0x384 [btrfs] [<ffffffffa036506f>] btrfs_relocate_block_group+0x18d/0x312 [btrfs] [<ffffffffa034dfe7>] btrfs_relocate_chunk+0x6c/0x4c2 [btrfs] [<ffffffffa033e051>] ? btrfs_item_offset+0xbb/0xcb [btrfs] [<ffffffffa034c81b>] ? btrfs_item_key_to_cpu+0x2a/0x46 [btrfs] [<ffffffffa034ea24>] btrfs_balance+0x1ce/0x21b [btrfs] [<ffffffff811f02b0>] ? inode_has_perm+0xaa/0xce [<ffffffffa0355cec>] btrfs_ioctl+0x6f9/0x871 [btrfs] [<ffffffff81071226>] ? sched_clock_cpu+0xc3/0xce [<ffffffff8107ba94>] ? trace_hardirqs_off+0xd/0xf [<ffffffff81071274>] ? cpu_clock+0x43/0x5e [<ffffffff8112c054>] vfs_ioctl+0x32/0xa6 [<ffffffff8112c5d4>] do_vfs_ioctl+0x490/0x4d6 [<ffffffff8112c670>] sys_ioctl+0x56/0x79 [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b Code: 47 48 48 85 c0 74 04 31 f6 ff d0 48 83 c4 28 5b 41 5c 41 5d c9 c3 55 48 89 e5 0f 1f 44 00 00 83 7e 10 00 48 89 d0 48 89 ca 74 23 <f6> 40 75 10 74 0d 4c 89 c1 48 89 c6 e8 3d fb ff ff eb 10 4d 89 RIP [<ffffffff810e380f>] page_cache_sync_readahead+0x15/0x3a RSP <ffff88003309fac8> CR2: 0000000000000075 ---[ end trace 1b855fa188411071 ]--- Sean -- Sean Reifschneider, Member of Technical Staff <jafo@xxxxxxxxx> tummy.com, ltd. - Linux Consulting since 1995: Ask me about High Availability
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