I hope this is of use. After recovering the RAID, the drives were used heavily, backing up and restoring, A while later, Arch Linux hung for unknown reasons and after reset (Intel ME reset: as before, the o/s was unresponsive) the RAID began a resync. I resumed copying etc, discs busy, and ran 'find / something', which hung. After a while everything resumed without apparent harm. Here are extracts from journalctl: Jan 11 10:20:27 archlinux kernel: Linux version 4.2.5-1-ARCH (builduser@tobias) (gcc version 5.2.0 (GCC) ) #1 SMP PREEMPT Tue Oct 27 08:13:28 CET 2015 ... Jan 11 10:20:27 archlinux kernel: DMI: VIGLEN DQ77MK/DQ77MK, BIOS MKQ7710H.86A.0062.2013.0902.1328 09/02/2013 ... Jan 11 10:20:27 archlinux kernel: raid6: sse2x1 gen() 6958 MB/s Jan 11 10:20:27 archlinux kernel: random: nonblocking pool is initialized Jan 11 10:20:27 archlinux kernel: raid6: sse2x1 xor() 6766 MB/s Jan 11 10:20:27 archlinux kernel: raid6: sse2x2 gen() 12676 MB/s Jan 11 10:20:27 archlinux kernel: raid6: sse2x2 xor() 8365 MB/s Jan 11 10:20:27 archlinux kernel: raid6: sse2x4 gen() 10430 MB/s Jan 11 10:20:27 archlinux kernel: raid6: sse2x4 xor() 7014 MB/s Jan 11 10:20:27 archlinux kernel: raid6: using algorithm sse2x2 gen() 12676 MB/s Jan 11 10:20:27 archlinux kernel: raid6: .... xor() 8365 MB/s, rmw enabled Jan 11 10:20:27 archlinux kernel: raid6: using ssse3x2 recovery algorithm Jan 11 10:20:27 archlinux kernel: async_tx: api initialized (async) Jan 11 10:20:27 archlinux kernel: xor: automatically using best checksumming function: Jan 11 10:20:27 archlinux kernel: avx : 27582.000 MB/sec Jan 11 10:20:27 archlinux kernel: md: raid6 personality registered for level 6 Jan 11 10:20:27 archlinux kernel: md: raid5 personality registered for level 5 Jan 11 10:20:27 archlinux kernel: md: raid4 personality registered for level 4 Jan 11 10:20:27 archlinux kernel: md/raid:md126: device sdd operational as raid disk 0 Jan 11 10:20:27 archlinux kernel: md/raid:md126: device sda operational as raid disk 1 Jan 11 10:20:27 archlinux kernel: md/raid:md126: device sdc operational as raid disk 2 Jan 11 10:20:27 archlinux kernel: md/raid:md126: device sdb operational as raid disk 3 Jan 11 10:20:27 archlinux kernel: md/raid:md126: allocated 4366kB Jan 11 10:20:27 archlinux kernel: md/raid:md126: raid level 5 active with 4 out of 4 devices, algorithm 0 Jan 11 10:20:27 archlinux kernel: RAID conf printout: Jan 11 10:20:27 archlinux kernel: --- level:5 rd:4 wd:4 Jan 11 10:20:27 archlinux kernel: disk 0, o:1, dev:sdd Jan 11 10:20:27 archlinux kernel: disk 1, o:1, dev:sda Jan 11 10:20:27 archlinux kernel: disk 2, o:1, dev:sdc Jan 11 10:20:27 archlinux kernel: disk 3, o:1, dev:sdb Jan 11 10:20:27 archlinux kernel: md126: detected capacity change from 0 to 101494816768 Jan 11 10:20:27 archlinux kernel: md: md126 switched to read-write mode. Jan 11 10:20:27 archlinux kernel: md: bind<sdb> Jan 11 10:20:27 archlinux kernel: md: bind<sdc> Jan 11 10:20:27 archlinux kernel: md: bind<sda> Jan 11 10:20:27 archlinux kernel: md: bind<sdd> Jan 11 10:20:27 archlinux kernel: md/raid:md125: not clean -- starting background reconstruction Jan 11 10:20:27 archlinux kernel: md/raid:md125: device sdd operational as raid disk 0 Jan 11 10:20:27 archlinux kernel: md/raid:md125: device sda operational as raid disk 1 Jan 11 10:20:27 archlinux kernel: md/raid:md125: device sdc operational as raid disk 2 Jan 11 10:20:27 archlinux kernel: md/raid:md125: device sdb operational as raid disk 3 Jan 11 10:20:27 archlinux kernel: md/raid:md125: allocated 4366kB Jan 11 10:20:27 archlinux kernel: md/raid:md125: raid level 5 active with 4 out of 4 devices, algorithm 0 Jan 11 10:20:27 archlinux kernel: RAID conf printout: Jan 11 10:20:27 archlinux kernel: --- level:5 rd:4 wd:4 Jan 11 10:20:27 archlinux kernel: disk 0, o:1, dev:sdd Jan 11 10:20:27 archlinux kernel: disk 1, o:1, dev:sda Jan 11 10:20:27 archlinux kernel: disk 2, o:1, dev:sdc Jan 11 10:20:27 archlinux kernel: disk 3, o:1, dev:sdb Jan 11 10:20:27 archlinux kernel: md125: detected capacity change from 0 to 2899102924800 Jan 11 10:20:27 archlinux kernel: md: md125 switched to read-write mode. Jan 11 10:20:27 archlinux kernel: md: resync of RAID array md125 Jan 11 10:20:27 archlinux kernel: md: minimum _guaranteed_ speed: 1000 KB/sec/disk. Jan 11 10:20:27 archlinux kernel: md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for resync. Jan 11 10:20:27 archlinux kernel: md: using 128k window, over a total of 943718400k. Jan 11 10:20:27 archlinux kernel: md: resuming resync of md125 from checkpoint. Jan 11 10:20:27 archlinux kernel: md125: p1 p2 p3 Jan 11 10:20:27 archlinux kernel: device-mapper: uevent: version 1.0.3 Jan 11 10:20:27 archlinux kernel: device-mapper: ioctl: 4.33.0-ioctl (2015-8-18) initialised: dm-devel@xxxxxxxxxx Jan 11 10:20:27 archlinux kernel: EXT4-fs (dm-2): mounted filesystem with ordered data mode. Opts: (null) ... Jan 11 10:20:27 archlinux kernel: EXT4-fs (dm-2): re-mounted. Opts: stripe=64,data=ordered ... Jan 11 10:35:17 archlinux systemd[1]: Starting Cleanup of Temporary Directories... Jan 11 10:35:18 archlinux systemd[1]: Started Cleanup of Temporary Directories. ... Jan 11 10:40:13 archlinux kernel: INFO: task jbd2/dm-2-8:325 blocked for more than 120 seconds. Jan 11 10:40:13 archlinux kernel: Not tainted 4.2.5-1-ARCH #1 Jan 11 10:40:13 archlinux kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Jan 11 10:40:13 archlinux kernel: jbd2/dm-2-8 D ffff88042e255200 0 325 2 0x00000000 Jan 11 10:40:13 archlinux kernel: ffff880418d97c78 0000000000000046 ffff88041c279b80 ffff880418943700 Jan 11 10:40:13 archlinux kernel: 0000000000000001 ffff880418d98000 ffff880418d97d70 ffff880418d97d58 Jan 11 10:40:13 archlinux kernel: ffff880418943700 ffff8804182e5400 ffff880418d97c98 ffffffff8157283e Jan 11 10:40:13 archlinux kernel: Call Trace: Jan 11 10:40:13 archlinux kernel: [<ffffffff8157283e>] schedule+0x3e/0x90 Jan 11 10:40:13 archlinux kernel: [<ffffffffa02344e1>] jbd2_journal_commit_transaction+0x231/0x1890 [jbd2] Jan 11 10:40:13 archlinux kernel: [<ffffffff810a8239>] ? dequeue_entity+0x149/0x690 Jan 11 10:40:13 archlinux kernel: [<ffffffff810a9071>] ? put_prev_entity+0x31/0x420 Jan 11 10:40:13 archlinux kernel: [<ffffffff810b4c80>] ? wake_atomic_t_function+0x60/0x60 Jan 11 10:40:13 archlinux kernel: [<ffffffff810dca8e>] ? try_to_del_timer_sync+0x5e/0x90 Jan 11 10:40:13 archlinux kernel: [<ffffffffa023ab4a>] kjournald2+0xca/0x250 [jbd2] Jan 11 10:40:13 archlinux kernel: [<ffffffff810b4c80>] ? wake_atomic_t_function+0x60/0x60 Jan 11 10:40:13 archlinux kernel: [<ffffffffa023aa80>] ? commit_timeout+0x10/0x10 [jbd2] Jan 11 10:40:13 archlinux kernel: [<ffffffff81092578>] kthread+0xd8/0xf0 Jan 11 10:40:13 archlinux kernel: [<ffffffff810924a0>] ? kthread_worker_fn+0x170/0x170 Jan 11 10:40:13 archlinux kernel: [<ffffffff8157665f>] ret_from_fork+0x3f/0x70 Jan 11 10:40:13 archlinux kernel: [<ffffffff810924a0>] ? kthread_worker_fn+0x170/0x170 Jan 11 10:40:13 archlinux kernel: INFO: task find:1536 blocked for more than 120 seconds. Jan 11 10:40:13 archlinux kernel: Not tainted 4.2.5-1-ARCH #1 Jan 11 10:40:13 archlinux kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Jan 11 10:40:13 archlinux kernel: find D 0000000000000001 0 1536 1262 0x00000004 Jan 11 10:40:13 archlinux kernel: ffff8800b726b9e8 0000000000000082 ffff8800b10fe040 ffff8804173244c0 Jan 11 10:40:13 archlinux kernel: ffff8800b726b9d8 ffff8800b726c000 ffff88042e255200 7fffffffffffffff Jan 11 10:40:13 archlinux kernel: 0000000000000002 ffffffff81573110 ffff8800b726ba08 ffffffff8157283e Jan 11 10:40:13 archlinux kernel: Call Trace: Jan 11 10:40:13 archlinux kernel: [<ffffffff81573110>] ? bit_wait+0x50/0x50 Jan 11 10:40:13 archlinux kernel: [<ffffffff8157283e>] schedule+0x3e/0x90 Jan 11 10:40:13 archlinux kernel: [<ffffffff81575205>] schedule_timeout+0x1b5/0x240 Jan 11 10:40:13 archlinux kernel: [<ffffffff8101e769>] ? read_tsc+0x9/0x10 Jan 11 10:40:13 archlinux kernel: [<ffffffff811115e6>] ? delayacct_end+0x56/0x60 Jan 11 10:40:13 archlinux kernel: [<ffffffff8101e769>] ? read_tsc+0x9/0x10 Jan 11 10:40:13 archlinux kernel: [<ffffffff81573110>] ? bit_wait+0x50/0x50 Jan 11 10:40:13 archlinux kernel: [<ffffffff81571d94>] io_schedule_timeout+0xa4/0x110 Jan 11 10:40:13 archlinux kernel: [<ffffffff810b4744>] ? prepare_to_wait_exclusive+0x54/0x80 Jan 11 10:40:13 archlinux kernel: [<ffffffff81573145>] bit_wait_io+0x35/0x50 Jan 11 10:40:13 archlinux kernel: [<ffffffff81572f2b>] __wait_on_bit_lock+0x4b/0xa0 Jan 11 10:40:13 archlinux kernel: [<ffffffff81573110>] ? bit_wait+0x50/0x50 Jan 11 10:40:13 archlinux kernel: [<ffffffff81573002>] out_of_line_wait_on_bit_lock+0x82/0xb0 Jan 11 10:40:13 archlinux kernel: [<ffffffff810b4cc0>] ? autoremove_wake_function+0x40/0x40 Jan 11 10:40:13 archlinux kernel: [<ffffffff810b4cc0>] ? autoremove_wake_function+0x40/0x40 Jan 11 10:40:13 archlinux kernel: [<ffffffff81203f67>] __lock_buffer+0x27/0x30 Jan 11 10:40:13 archlinux kernel: [<ffffffffa0232b6c>] do_get_write_access+0x1ec/0x510 [jbd2] Jan 11 10:40:13 archlinux kernel: [<ffffffffa024a80f>] ? ext4_htree_store_dirent+0xdf/0x120 [ext4] Jan 11 10:40:13 archlinux kernel: [<ffffffff812058ca>] ? __find_get_block+0xaa/0x110 Jan 11 10:40:13 archlinux kernel: [<ffffffffa0232ec7>] jbd2_journal_get_write_access+0x37/0x70 [jbd2] Jan 11 10:40:13 archlinux kernel: [<ffffffffa0283391>] __ext4_journal_get_write_access+0x31/0x70 [ext4] Jan 11 10:40:13 archlinux kernel: [<ffffffffa0253de5>] ext4_reserve_inode_write+0x75/0xa0 [ext4] Jan 11 10:40:13 archlinux kernel: [<ffffffffa0257388>] ? ext4_dirty_inode+0x48/0x70 [ext4] Jan 11 10:40:13 archlinux kernel: [<ffffffffa0253e5e>] ext4_mark_inode_dirty+0x4e/0x220 [ext4] Jan 11 10:40:13 archlinux kernel: [<ffffffffa0257388>] ext4_dirty_inode+0x48/0x70 [ext4] Jan 11 10:40:13 archlinux kernel: [<ffffffff811fc648>] __mark_inode_dirty+0x48/0x380 Jan 11 10:40:13 archlinux kernel: [<ffffffff811ea579>] generic_update_time+0x79/0xc0 Jan 11 10:40:13 archlinux kernel: [<ffffffff811ebde6>] touch_atime+0xa6/0xd0 Jan 11 10:40:13 archlinux kernel: [<ffffffff811e2ebb>] iterate_dir+0xdb/0x120 Jan 11 10:40:13 archlinux kernel: [<ffffffff811e330d>] SyS_getdents+0x8d/0x100 Jan 11 10:40:13 archlinux kernel: [<ffffffff811e2fd0>] ? fillonedir+0xd0/0xd0 Jan 11 10:40:13 archlinux kernel: [<ffffffff8157626e>] entry_SYSCALL_64_fastpath+0x12/0x71 ... -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
