[LU-12062] sanity-benchmark test iozone hangs with “too many service threads, or there were not enough hardware resources”

• Status: Resolved
• Project: Lustre
• Affects Version/s: Lustre 2.10.7
• Type: Bug
• Priority: Minor
• Reporter: James Nunez (Inactive)
• Assignee: WC Triage
• Resolution: Cannot Reproduce
• Labels: ZFS

Environment

ZFS

• Severity: 3

Description

sanity-benchmark test_iozone hangs. So far, we’re only seeing this hang for ZFS.

Looking at the suite_log for the failure at https://testing.whamcloud.com/test_sets/464d518e-43e5-11e9-a256-52540065bddc, we can see iozone hangs in DirectIO testing

== sanity-benchmark test iozone: iozone ============================================================== 15:04:32 (1552143872)
min OST has 1922432kB available, using 3438744kB file size
debug=0
running as uid/gid/euid/egid 500/500/500/500, groups:
 [touch] [/mnt/lustre/d0_runas_test/f27932]
running as uid/gid/euid/egid 500/500/500/500, groups:
 [iozone] [-i] [0] [-i] [1] [-i] [2] [-e] [-+d] [-r] [512] [-s] [3438744] [-f] [/mnt/lustre/d0.iozone/iozone]
	Iozone: Performance Test of File I/O
	        Version $Revision: 3.373 $
		Compiled for 64 bit mode.
		Build: linux-AMD64 

	Contributors:William Norcott, Don Capps, Isom Crawford, Kirby Collins
	             Al Slater, Scott Rhine, Mike Wisner, Ken Goss
	             Steve Landherr, Brad Smith, Mark Kelly, Dr. Alain CYR,
	             Randy Dunlap, Mark Montague, Dan Million, Gavin Brebner,
	             Jean-Marc Zucconi, Jeff Blomberg, Benny Halevy, Dave Boone,
	             Erik Habbinga, Kris Strecker, Walter Wong, Joshua Root,
	             Fabrice Bacchella, Zhenghua Xue, Qin Li, Darren Sawyer.

	Run began: Sat Mar  9 15:04:38 2019

	Include fsync in write timing
	>>> I/O Diagnostic mode enabled. <<<
	Performance measurements are invalid in this mode.
	Record Size 512 KB
	File size set to 3438744 KB
	Command line used: iozone -i 0 -i 1 -i 2 -e -+d -r 512 -s 3438744 -f /mnt/lustre/d0.iozone/iozone
	Output is in Kbytes/sec
	Time Resolution = 0.000001 seconds.
	Processor cache size set to 1024 Kbytes.
	Processor cache line size set to 32 bytes.
	File stride size set to 17 * record size.
                                                            random  random    bkwd   record   stride                                   
              KB  reclen   write rewrite    read    reread    read   write    read  rewrite     read   fwrite frewrite   fread  freread
         3438744     512    2826    2713    32747    35474   19214    3473                                                          

iozone test complete.
debug=0x33f0484
directio on /mnt/lustre/f.iozone for 1x4194304 bytes 
PASS
debug=0
running as uid/gid/euid/egid 500/500/500/500, groups:
 [iozone] [-I] [-i] [0] [-i] [1] [-i] [2] [-e] [-+d] [-r] [512] [-s] [3438744] [-f] [/mnt/lustre/d0.iozone/iozone.odir]
	Iozone: Performance Test of File I/O
	        Version $Revision: 3.373 $
		Compiled for 64 bit mode.
		Build: linux-AMD64 

	Contributors:William Norcott, Don Capps, Isom Crawford, Kirby Collins
	             Al Slater, Scott Rhine, Mike Wisner, Ken Goss
	             Steve Landherr, Brad Smith, Mark Kelly, Dr. Alain CYR,
	             Randy Dunlap, Mark Montague, Dan Million, Gavin Brebner,
	             Jean-Marc Zucconi, Jeff Blomberg, Benny Halevy, Dave Boone,
	             Erik Habbinga, Kris Strecker, Walter Wong, Joshua Root,
	             Fabrice Bacchella, Zhenghua Xue, Qin Li, Darren Sawyer.

	Run began: Sat Mar  9 16:08:59 2019

	O_DIRECT feature enabled
	Include fsync in write timing
	>>> I/O Diagnostic mode enabled. <<<
	Performance measurements are invalid in this mode.
	Record Size 512 KB
	File size set to 3438744 KB
	Command line used: iozone -I -i 0 -i 1 -i 2 -e -+d -r 512 -s 3438744 -f /mnt/lustre/d0.iozone/iozone.odir
	Output is in Kbytes/sec
	Time Resolution = 0.000001 seconds.
	Processor cache size set to 1024 Kbytes.
	Processor cache line size set to 32 bytes.
	File stride size set to 17 * record size.
                                                            random  random    bkwd   record   stride                                   
              KB  reclen   write rewrite    read    reread    read   write    read  rewrite     read   fwrite frewrite   fread  freread
         3438744     512

Looking at the console logs, there’s not a lot to go on. On the OSS (vm3) we do see an LNET too many service threads warning before the hang and looking through the call stacks, there are some processes in the D state

[22345.851895] Lustre: DEBUG MARKER: == sanity-benchmark test iozone: iozone ============================================================== 15:04:32 (1552143872)
[22349.818428] Lustre: DEBUG MARKER: /usr/sbin/lctl mark min OST has 1922432kB available, using 3438744kB file size
[22350.076310] Lustre: DEBUG MARKER: min OST has 1922432kB available, using 3438744kB file size
[22402.060402] LNet: Service thread pid 32137 completed after 41.38s. This indicates the system was overloaded (too many service threads, or there were not enough hardware resources).
[22402.065241] LNet: Skipped 7 previous similar messages
[22410.807172] LNet: Service thread pid 1390 completed after 50.25s. This indicates the system was overloaded (too many service threads, or there were not enough hardware resources).
[22410.812202] LNet: Skipped 4 previous similar messages
[22431.196168] LNet: Service thread pid 10091 completed after 70.64s. This indicates the system was overloaded (too many service threads, or there were not enough hardware resources).
[22431.199270] LNet: Skipped 21 previous similar messages
[23561.656188] LNet: Service thread pid 19365 completed after 50.37s. This indicates the system was overloaded (too many service threads, or there were not enough hardware resources).
[23561.659104] LNet: Skipped 23 previous similar messages
[23566.276500] LNet: Service thread pid 1643 completed after 54.99s. This indicates the system was overloaded (too many service threads, or there were not enough hardware resources).
[23566.280050] LNet: Skipped 1 previous similar message
[24830.125602] LNet: Service thread pid 1385 completed after 44.33s. This indicates the system was overloaded (too many service threads, or there were not enough hardware resources).
[24830.129505] LNet: Skipped 4 previous similar messages
[24832.949732] LNet: Service thread pid 23024 completed after 47.15s. This indicates the system was overloaded (too many service threads, or there were not enough hardware resources).
[24836.845387] LNet: Service thread pid 30496 completed after 51.05s. This indicates the system was overloaded (too many service threads, or there were not enough hardware resources).
…
[36836.448221] jbd2/vda1-8     D ffff8c47b92ac100     0  1197      2 0x00000000
[36836.449552] Call Trace:
[36836.450017]  [<ffffffffa2d65d60>] ? bit_wait+0x50/0x50
[36836.450882]  [<ffffffffa2d67c49>] schedule+0x29/0x70
[36836.451724]  [<ffffffffa2d65721>] schedule_timeout+0x221/0x2d0
[36836.452739]  [<ffffffffa266a0ce>] ? kvm_clock_get_cycles+0x1e/0x20
[36836.453789]  [<ffffffffa2d65d60>] ? bit_wait+0x50/0x50
[36836.454659]  [<ffffffffa2d672ed>] io_schedule_timeout+0xad/0x130
[36836.455683]  [<ffffffffa2d67388>] io_schedule+0x18/0x20
[36836.456574]  [<ffffffffa2d65d71>] bit_wait_io+0x11/0x50
[36836.457463]  [<ffffffffa2d65897>] __wait_on_bit+0x67/0x90
[36836.458367]  [<ffffffffa2d65d60>] ? bit_wait+0x50/0x50
[36836.459228]  [<ffffffffa2d65a01>] out_of_line_wait_on_bit+0x81/0xb0
[36836.460283]  [<ffffffffa26c2dc0>] ? wake_bit_function+0x40/0x40
[36836.461282]  [<ffffffffa2878f1a>] __wait_on_buffer+0x2a/0x30
[36836.462460]  [<ffffffffc01e4801>] jbd2_journal_commit_transaction+0x1781/0x19b0 [jbd2]
[36836.463787]  [<ffffffffa26d0880>] ? finish_task_switch+0x50/0x1c0
[36836.464819]  [<ffffffffc01e9e89>] kjournald2+0xc9/0x260 [jbd2]
[36836.465805]  [<ffffffffa26c2d00>] ? wake_up_atomic_t+0x30/0x30
[36836.466785]  [<ffffffffc01e9dc0>] ? commit_timeout+0x10/0x10 [jbd2]
[36836.467836]  [<ffffffffa26c1c31>] kthread+0xd1/0xe0
[36836.468658]  [<ffffffffa26c1b60>] ? insert_kthread_work+0x40/0x40
[36836.469680]  [<ffffffffa2d74c37>] ret_from_fork_nospec_begin+0x21/0x21
[36836.470778]  [<ffffffffa26c1b60>] ? insert_kthread_work+0x40/0x40
…
[36836.877778] auditd          D ffff8c47b9094100     0  3085      1 0x00000000
[36836.879028] Call Trace:
[36836.879461]  [<ffffffffa2d67c49>] schedule+0x29/0x70
[36836.880296]  [<ffffffffc01e97c5>] jbd2_log_wait_commit+0xc5/0x140 [jbd2]
[36836.881405]  [<ffffffffa26c2d00>] ? wake_up_atomic_t+0x30/0x30
[36836.882391]  [<ffffffffc01eae52>] jbd2_complete_transaction+0x52/0xa0 [jbd2]
[36836.883626]  [<ffffffffc0213782>] ext4_sync_file+0x292/0x320 [ext4]
[36836.884681]  [<ffffffffa2875ef7>] do_fsync+0x67/0xb0
[36836.885533]  [<ffffffffa2d74d15>] ? system_call_after_swapgs+0xa2/0x146
[36836.886642]  [<ffffffffa28761e0>] SyS_fsync+0x10/0x20
[36836.887505]  [<ffffffffa2d74ddb>] system_call_fastpath+0x22/0x27
[36836.888528]  [<ffffffffa2d74d21>] ? system_call_after_swapgs+0xae/0x146
…
[36837.709648] in:imjournal    D ffff8c474007e180     0  3675      1 0x00000080
[36837.711149] Call Trace:
[36837.711590]  [<ffffffffa2d65d60>] ? bit_wait+0x50/0x50
[36837.712459]  [<ffffffffa2d67c49>] schedule+0x29/0x70
[36837.713287]  [<ffffffffa2d65721>] schedule_timeout+0x221/0x2d0
[36837.714256]  [<ffffffffa266a0ce>] ? kvm_clock_get_cycles+0x1e/0x20
[36837.715294]  [<ffffffffa2701052>] ? ktime_get_ts64+0x52/0xf0
[36837.716247]  [<ffffffffa2d65d60>] ? bit_wait+0x50/0x50
[36837.717120]  [<ffffffffa2d672ed>] io_schedule_timeout+0xad/0x130
[36837.718128]  [<ffffffffa2d67388>] io_schedule+0x18/0x20
[36837.719016]  [<ffffffffa2d65d71>] bit_wait_io+0x11/0x50
[36837.719907]  [<ffffffffa2d65897>] __wait_on_bit+0x67/0x90
[36837.720823]  [<ffffffffa27b92be>] ? __find_get_pages+0x11e/0x1c0
[36837.721834]  [<ffffffffa27b5761>] wait_on_page_bit+0x81/0xa0
[36837.722787]  [<ffffffffa26c2dc0>] ? wake_bit_function+0x40/0x40
[36837.723784]  [<ffffffffa27c6f4b>] truncate_inode_pages_range+0x42b/0x700
[36837.724937]  [<ffffffffc024bdbc>] ? __ext4_journal_stop+0x3c/0xb0 [ext4]
[36837.726062]  [<ffffffffc0227d58>] ? ext4_rename+0x168/0x890 [ext4]
[36837.727101]  [<ffffffffa2850d51>] ? link_path_walk+0x81/0x8b0
[36837.728084]  [<ffffffffa28aee8a>] ? __dquot_initialize+0x3a/0x240
[36837.729106]  [<ffffffffa286fa5a>] ? __inode_wait_for_writeback+0x7a/0xf0
[36837.730234]  [<ffffffffa27c728f>] truncate_inode_pages_final+0x4f/0x60
[36837.731330]  [<ffffffffc021e41f>] ext4_evict_inode+0x10f/0x480 [ext4]
[36837.732411]  [<ffffffffa285eab4>] evict+0xb4/0x180
[36837.733242]  [<ffffffffa285f3bc>] iput+0xfc/0x190
[36837.734048]  [<ffffffffa2859c20>] __dentry_kill+0x120/0x180
[36837.734987]  [<ffffffffa2859d30>] dput+0xb0/0x160
[36837.735793]  [<ffffffffa2853b58>] SYSC_renameat2+0x518/0x5a0
[36837.736751]  [<ffffffffa27ef841>] ? __vma_rb_erase+0x121/0x220
[36837.737731]  [<ffffffffa2d74d21>] ? system_call_after_swapgs+0xae/0x146
[36837.738835]  [<ffffffffa2d74d15>] ? system_call_after_swapgs+0xa2/0x146
[36837.739945]  [<ffffffffa2d74d21>] ? system_call_after_swapgs+0xae/0x146
[36837.741050]  [<ffffffffa2d74d15>] ? system_call_after_swapgs+0xa2/0x146
[36837.742152]  [<ffffffffa2854a5e>] SyS_renameat2+0xe/0x10
[36837.743078]  [<ffffffffa2854a9e>] SyS_rename+0x1e/0x20
[36837.743951]  [<ffffffffa2d74ddb>] system_call_fastpath+0x22/0x27
[36837.744961]  [<ffffffffa2d74d21>] ? system_call_after_swapgs+0xae/0x146
…
[36842.351359] txg_sync        D ffff8c478a3d5140     0 11265      2 0x00000080
[36842.352621] Call Trace:
[36842.353049]  [<ffffffffa287e565>] ? bio_alloc_bioset+0x115/0x310
[36842.354043]  [<ffffffffa2d67c49>] schedule+0x29/0x70
[36842.354892]  [<ffffffffa2d65721>] schedule_timeout+0x221/0x2d0
[36842.355886]  [<ffffffffa266a0ce>] ? kvm_clock_get_cycles+0x1e/0x20
[36842.356935]  [<ffffffffa2701052>] ? ktime_get_ts64+0x52/0xf0
[36842.357893]  [<ffffffffa2d672ed>] io_schedule_timeout+0xad/0x130
[36842.358912]  [<ffffffffa26c2886>] ? prepare_to_wait_exclusive+0x56/0x90
[36842.360046]  [<ffffffffa2d67388>] io_schedule+0x18/0x20
[36842.360935]  [<ffffffffc0367242>] cv_wait_common+0xb2/0x150 [spl]
[36842.361962]  [<ffffffffa26c2d00>] ? wake_up_atomic_t+0x30/0x30
[36842.362944]  [<ffffffffc0367318>] __cv_wait_io+0x18/0x20 [spl]
[36842.363963]  [<ffffffffc053b073>] zio_wait+0x113/0x1c0 [zfs]
[36842.364943]  [<ffffffffc04efbf1>] vdev_config_sync+0xf1/0x180 [zfs]
[36842.366027]  [<ffffffffc04cfa9c>] spa_sync+0xa1c/0xd90 [zfs]
[36842.366985]  [<ffffffffa26d67c2>] ? default_wake_function+0x12/0x20
[36842.368064]  [<ffffffffc04e3c71>] txg_sync_thread+0x301/0x510 [zfs]
[36842.369139]  [<ffffffffc04e3970>] ? txg_fini+0x2a0/0x2a0 [zfs]
[36842.370141]  [<ffffffffc0362063>] thread_generic_wrapper+0x73/0x80 [spl]
[36842.371269]  [<ffffffffc0361ff0>] ? __thread_exit+0x20/0x20 [spl]
[36842.372345]  [<ffffffffa26c1c31>] kthread+0xd1/0xe0
[36842.373182]  [<ffffffffa26c1b60>] ? insert_kthread_work+0x40/0x40
[36842.374210]  [<ffffffffa2d74c37>] ret_from_fork_nospec_begin+0x21/0x21
[36842.375312]  [<ffffffffa26c1b60>] ? insert_kthread_work+0x40/0x40

Could this be LU-8215 ?

Other sanity-benchmark test iozone that fail in this way
https://testing.whamcloud.com/test_sets/8d4b2322-4269-11e9-8e92-52540065bddc
https://testing.whamcloud.com/test_sets/c6afa400-4280-11e9-92fe-52540065bddc
https://testing.whamcloud.com/test_sets/c681c26c-40a8-11e9-8e92-52540065bddc
https://testing.whamcloud.com/test_sets/2e66b0c6-40aa-11e9-b98a-52540065bddc

Comments

[Andreas Dilger]

Since this is not running on real hardware, it seems possible that the high load is just overloading the VM guest/host due to a lot of IO. This is made worse by ZFS because (AFAIK) the host only has a single virtual disk for each guest, but ZFS expects to store redundant metadata copies, so it is writing 2x copies of all metadata to different parts of the "disk" and executing a lot of sync operations to do transaction commits.

Do we have enough RAM on the host to be able to store the host virtual disks directly in /tmp using tmpfs rather than on a real HDD? If the HDD used today for the virtual disks was made into a large swap device then the guest devices in /tmp can be spilled into swap if needed, but will mostly be served from RAM and swap is no slower than 7 OSTs and 4 MDTs all writing to a single HDD on the host.

We don't really care about the persistence of the guest filesystems if the host crashes, so there shouldn't be a problem. Even for "hard failover" tests, the virtual devices in /tmp would be available to all guests on the same host, the same as with a local HDD.

[Alena Nikitenko]

Might have happened here: https://testing.whamcloud.com/test_sets/e89234ef-9630-40e4-abf4-feca3da9762f 

2.12.8 sanity-benchmark test iozone on ZFS hangs under IO:

...
        Run began: Sat Nov 20 05:00:05 2021

	O_DIRECT feature enabled
	Include fsync in write timing
	>>> I/O Diagnostic mode enabled. <<<
	Performance measurements are invalid in this mode.
	Record Size 512 kB
	File size set to 5502664 kB
	Command line used: iozone -I -i 0 -i 1 -i 2 -e -+d -r 512 -s 5502664 -f /mnt/lustre/d0.iozone/iozone.odir
	Output is in kBytes/sec
	Time Resolution = 0.000001 seconds.
	Processor cache size set to 1024 kBytes.
	Processor cache line size set to 32 bytes.
	File stride size set to 17 * record size.
                                                              random    random     bkwd    record    stride                                    
              kB  reclen    write  rewrite    read    reread    read     write     read   rewrite      read   fwrite frewrite    fread  freread
         5502664     512 

[22327.751978] ll_ost_io00_063 D ffff97f5b9a1d280     0 26250      2 0x00000080
[22327.753328] Call Trace:
[22327.753790]  [<ffffffff89589179>] schedule+0x29/0x70
[22327.754705]  [<ffffffff89586e41>] schedule_timeout+0x221/0x2d0
[22327.755872]  [<ffffffffc066e569>] ? arc_read+0x499/0xab0 [zfs]
[22327.756947]  [<ffffffff88e6d39e>] ? kvm_clock_get_cycles+0x1e/0x20
[22327.758168]  [<ffffffff89588a2d>] io_schedule_timeout+0xad/0x130
[22327.759318]  [<ffffffff88ec6ad6>] ? prepare_to_wait_exclusive+0x56/0x90
[22327.760531]  [<ffffffff89588ac8>] io_schedule+0x18/0x20
[22327.761529]  [<ffffffffc02d7262>] cv_wait_common+0xb2/0x150 [spl]
[22327.762636]  [<ffffffff88ec6f50>] ? wake_up_atomic_t+0x30/0x30
[22327.763703]  [<ffffffffc02d7338>] __cv_wait_io+0x18/0x20 [spl]
[22327.764885]  [<ffffffffc0738a8b>] zio_wait+0x11b/0x1c0 [zfs]
[22327.766007]  [<ffffffffc0695251>] dmu_tx_count_write+0x191/0x1d0 [zfs]
[22327.767227]  [<ffffffffc069532a>] dmu_tx_hold_write_by_dnode+0x3a/0x50 [zfs]
[22327.768579]  [<ffffffffc1185449>] osd_declare_write_commit+0x599/0x7f0 [osd_zfs]
[22327.769964]  [<ffffffffc069633b>] ? dmu_tx_create_dd+0x9b/0xe0 [zfs]
[22327.771150]  [<ffffffffc12c4739>] ofd_commitrw_write+0x939/0x1db0 [ofd]
[22327.772363]  [<ffffffffc12c8e1c>] ofd_commitrw+0x47c/0xa50 [ofd]
[22327.773572]  [<ffffffffc0f9fbec>] obd_commitrw+0x9c/0x370 [ptlrpc]
[22327.774739]  [<ffffffffc0fa4092>] tgt_brw_write+0xf02/0x1ae0 [ptlrpc]
[22327.775959]  [<ffffffffc0ade393>] ? cfs_trace_unlock_tcd+0x33/0x90 [libcfs]
[22327.777235]  [<ffffffffc0ae4cc8>] ? libcfs_debug_vmsg2+0x6d8/0xb30 [libcfs]
[22327.778585]  [<ffffffffc0ef5780>] ? target_send_reply_msg+0x170/0x170 [ptlrpc]
[22327.779932]  [<ffffffffc0fa5eea>] tgt_request_handle+0xada/0x1570 [ptlrpc]
[22327.781187]  [<ffffffffc0ae5177>] ? libcfs_debug_msg+0x57/0x80 [libcfs]
[22327.782418]  [<ffffffffc0f4abcb>] ptlrpc_server_handle_request+0x24b/0xab0 [ptlrpc]
[22327.783913]  [<ffffffffc0f4e534>] ptlrpc_main+0xb34/0x1470 [ptlrpc]
[22327.785118]  [<ffffffffc0f4da00>] ? ptlrpc_register_service+0xf80/0xf80 [ptlrpc]
[22327.786447]  [<ffffffff88ec5e61>] kthread+0xd1/0xe0
[22327.787448]  [<ffffffff88ec5d90>] ? insert_kthread_work+0x40/0x40
[22327.788567]  [<ffffffff89595df7>] ret_from_fork_nospec_begin+0x21/0x21
[22327.789751]  [<ffffffff88ec5d90>] ? insert_kthread_work+0x40/0x40