On Wed, May 15, 2019 at 9:34 PM Frank Schilder <[email protected]> wrote:
>
> Dear Stefan,
>
> thanks for the fast reply. We encountered the problem again, this time in a
> much simpler situation; please see below. However, let me start with your
> questions first:
>
> What bug? -- In a single-active MDS set-up, should there ever occur an
> operation with "op_name": "fragmentdir"?
>
> Trimming settings: In the version I'm running, mds_log_max_expiring does not
> exist and mds_log_max_segments is 128 by default. I guess this is fine.
>
> Upgrading: The problem described here is the only issue we observe. Unless
> the problem is fixed upstream, upgrading won't help us and would be a bit of
> a waste of time. If someone can confirm that this problem is fixed in a newer
> version, we will do it. Otherwise, we might prefer to wait until it is.
>
> News on the problem. We encountered it again when one of our users executed a
> command in parallel with pdsh on all our ~500 client nodes. This command
> accesses the same file from all these nodes pretty much simultaneously. We
> did this quite often in the past, but this time, the command got stuck and we
> started observing the MDS health problem again. Symptoms:
>
> - The pdsh process enters an un-interruptible state.
> - It is no longer possible to access the directory where the simultaneously
> accessed file resides (from any client).
> - 'ceph status' reports 'MDS slow requests'
> - The 'ceph daemon mds.nnn ops' list contains operations that are waiting for
> directory fragmentation (see full log below).
> - The ops list contains an operation "internal op fragmentdir:mds.0:35" that
> is dispatched, but apparently never completes.
> - Any attempt to access the locked directory adds operations to the ops list
> that will then also hang indefinitely.
> - I/O to other directories continues to work fine.
>
> We waited some time to confirm that ceph does not heal itself. It is a
> dead-lock situation that seems to be triggered by a large number of clients
> simultaneously accessing the same file/directory. This problem seems not to
> occur with 100 or fewer clients. The probability of occurrence seems load
> dependent.
>
> Temporary fix: Failing the active MDS flushed the stuck operations. The
> cluster became healthy and all clients rejoined.
>
> This time I captured the MDS ops list (log output does not really contain
> more info than this list). It contains 12 ops and I will include it here in
> full length (hope this is acceptable):
>
Your issues were caused by stuck internal op fragmentdir. Can you
dump mds cache and send the output to us?
> {
> "ops": [
> {
> "description": "client_request(client.386087:12791 lookup
> #0x10000000027/file.pdf 2019-05-15 11:30:47.173526 caller_uid=0,
> caller_gid=0{})",
> "initiated_at": "2019-05-15 11:30:47.174134",
> "age": 492.800243,
> "duration": 492.800277,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.386087:12791",
> "op_type": "client_request",
> "client_info": {
> "client": "client.386087",
> "tid": 12791
> },
> "events": [
> {
> "time": "2019-05-15 11:30:47.174134",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:30:47.174134",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:30:47.174136",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:30:47.174144",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:30:47.174245",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:30:47.174271",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> },
> {
> "description": "client_request(client.62472:6092355 create
> #0x10000000038/lastnotification.uXMjaLSt 2019-05-15 11:15:02.883027
> caller_uid=105731, caller_gid=105731{})",
> "initiated_at": "2019-05-15 11:15:02.884547",
> "age": 1437.089830,
> "duration": 1437.089937,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.62472:6092355",
> "op_type": "client_request",
> "client_info": {
> "client": "client.62472",
> "tid": 6092355
> },
> "events": [
> {
> "time": "2019-05-15 11:15:02.884547",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:15:02.884547",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:15:02.884552",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:15:02.884571",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:15:02.884721",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:15:02.884857",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> },
> {
> "description": "client_request(client.386087:12793 lookup
> #0x10000000027/file.pdf 2019-05-15 11:33:52.499279 caller_uid=0,
> caller_gid=0{})",
> "initiated_at": "2019-05-15 11:33:52.500354",
> "age": 307.474024,
> "duration": 307.474189,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.386087:12793",
> "op_type": "client_request",
> "client_info": {
> "client": "client.386087",
> "tid": 12793
> },
> "events": [
> {
> "time": "2019-05-15 11:33:52.500354",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:33:52.500354",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:33:52.500356",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:33:52.500393",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:33:52.500458",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:33:52.500482",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> },
> {
> "description": "client_request(client.377552:1989 lookup
> #0x10000000027/file.pdf 2019-05-15 11:40:44.566328 caller_uid=0,
> caller_gid=0{})",
> "initiated_at": "2019-05-15 11:36:13.509050",
> "age": 166.465328,
> "duration": 166.465529,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.377552:1989",
> "op_type": "client_request",
> "client_info": {
> "client": "client.377552",
> "tid": 1989
> },
> "events": [
> {
> "time": "2019-05-15 11:36:13.509050",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:36:13.509050",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:36:13.509052",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:36:13.509063",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:36:13.509163",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:36:13.509219",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> },
> {
> "description": "client_request(client.377552:1990 lookup
> #0x10000000027/file.pdf 2019-05-15 11:40:46.130328 caller_uid=0,
> caller_gid=0{})",
> "initiated_at": "2019-05-15 11:36:15.072708",
> "age": 164.901670,
> "duration": 164.901906,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.377552:1990",
> "op_type": "client_request",
> "client_info": {
> "client": "client.377552",
> "tid": 1990
> },
> "events": [
> {
> "time": "2019-05-15 11:36:15.072708",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:36:15.072708",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:36:15.072710",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:36:15.072719",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:36:15.072847",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:36:15.072881",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> },
> {
> "description": "client_request(client.62472:6092426 readdir
> #0x1000000002f 2019-05-15 11:21:53.080524 caller_uid=0, caller_gid=0{})",
> "initiated_at": "2019-05-15 11:21:53.081656",
> "age": 1026.892722,
> "duration": 1026.892997,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.62472:6092426",
> "op_type": "client_request",
> "client_info": {
> "client": "client.62472",
> "tid": 6092426
> },
> "events": [
> {
> "time": "2019-05-15 11:21:53.081656",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:21:53.081656",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:21:53.081658",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:21:53.081669",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:21:53.081772",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:21:53.081826",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> },
> {
> "description": "internal op fragmentdir:mds.0:35",
> "initiated_at": "2019-05-15 11:06:33.594105",
> "age": 1946.380273,
> "duration": 1946.380603,
> "type_data": {
> "flag_point": "dispatched",
> "reqid": "mds.0:35",
> "op_type": "internal_op",
> "internal_op": 5376,
> "op_name": "fragmentdir",
> "events": [
> {
> "time": "2019-05-15 11:06:33.594105",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:06:33.594105",
> "event": "header_read"
> },
> {
> "time": "0.000000",
> "event": "throttled"
> },
> {
> "time": "0.000000",
> "event": "all_read"
> },
> {
> "time": "0.000000",
> "event": "dispatched"
> }
> ]
> }
> },
> {
> "description": "client_request(client.386087:12786 lookup
> #0x10000000027/file.pdf 2019-05-15 11:22:06.783606 caller_uid=0,
> caller_gid=0{})",
> "initiated_at": "2019-05-15 11:22:06.784393",
> "age": 1013.189985,
> "duration": 1013.190344,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.386087:12786",
> "op_type": "client_request",
> "client_info": {
> "client": "client.386087",
> "tid": 12786
> },
> "events": [
> {
> "time": "2019-05-15 11:22:06.784393",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:22:06.784393",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:22:06.784394",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:22:06.784405",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:22:06.784506",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:22:06.784562",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> },
> {
> "description": "client_request(client.386087:12795 lookup
> #0x10000000027/file.pdf 2019-05-15 11:37:31.764353 caller_uid=0,
> caller_gid=0{})",
> "initiated_at": "2019-05-15 11:37:31.765631",
> "age": 88.208747,
> "duration": 88.209160,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.386087:12795",
> "op_type": "client_request",
> "client_info": {
> "client": "client.386087",
> "tid": 12795
> },
> "events": [
> {
> "time": "2019-05-15 11:37:31.765631",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:37:31.765631",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:37:31.765633",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:37:31.765640",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:37:31.765731",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:37:31.765759",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> },
> {
> "description": "client_request(client.377552:5446 readdir
> #0x1000000003a 2019-05-15 11:43:07.569329 caller_uid=0, caller_gid=0{})",
> "initiated_at": "2019-05-15 11:38:36.511381",
> "age": 23.462997,
> "duration": 23.463467,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.377552:5446",
> "op_type": "client_request",
> "client_info": {
> "client": "client.377552",
> "tid": 5446
> },
> "events": [
> {
> "time": "2019-05-15 11:38:36.511381",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:38:36.511381",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:38:36.511383",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:38:36.511392",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:38:36.511561",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:38:36.511604",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> },
> {
> "description": "client_request(client.62472:6092368 getattr
> pAsLsXsFs #0x10000000038 2019-05-15 11:17:21.633854 caller_uid=105731,
> caller_gid=105731{})",
> "initiated_at": "2019-05-15 11:17:21.635927",
> "age": 1298.338451,
> "duration": 1298.338955,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.62472:6092368",
> "op_type": "client_request",
> "client_info": {
> "client": "client.62472",
> "tid": 6092368
> },
> "events": [
> {
> "time": "2019-05-15 11:17:21.635927",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:17:21.635927",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:17:21.635931",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:17:21.635944",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:17:21.636081",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:17:21.636118",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> },
> {
> "description": "client_request(client.62472:6092400 getattr
> pAsLsXsFs #0x10000000038 2019-05-15 11:21:25.909555 caller_uid=105731,
> caller_gid=105731{})",
> "initiated_at": "2019-05-15 11:21:25.910514",
> "age": 1054.063864,
> "duration": 1054.064406,
> "type_data": {
> "flag_point": "failed to authpin, dir is being fragmented",
> "reqid": "client.62472:6092400",
> "op_type": "client_request",
> "client_info": {
> "client": "client.62472",
> "tid": 6092400
> },
> "events": [
> {
> "time": "2019-05-15 11:21:25.910514",
> "event": "initiated"
> },
> {
> "time": "2019-05-15 11:21:25.910514",
> "event": "header_read"
> },
> {
> "time": "2019-05-15 11:21:25.910527",
> "event": "throttled"
> },
> {
> "time": "2019-05-15 11:21:25.910537",
> "event": "all_read"
> },
> {
> "time": "2019-05-15 11:21:25.910597",
> "event": "dispatched"
> },
> {
> "time": "2019-05-15 11:21:25.910635",
> "event": "failed to authpin, dir is being fragmented"
> }
> ]
> }
> }
> ],
> "num_ops": 12
> }
>
> =================
> Frank Schilder
> AIT Ris? Campus
> Bygning 109, rum S14
>
> ________________________________________
> From: Stefan Kooman <[email protected]>
> Sent: 14 May 2019 09:54:05
> To: Frank Schilder
> Cc: [email protected]
> Subject: Re: [ceph-users] mimic: MDS standby-replay causing blocked ops (MDS
> bug?)
>
> Quoting Frank Schilder ([email protected]):
>
> If at all possible I would:
>
> Upgrade to 13.2.5 (there have been quite a few MDS fixes since 13.2.2).
> Use more recent kernels on the clients.
>
> Below settings for [mds] might help with trimming (you might already
> have changed mds_log_max_segments to 128 according to logs):
>
> [mds]
> mds_log_max_expiring = 80 # default 20
> # trim max $value segments in parallel
> # Defaults are too conservative.
> mds_log_max_segments = 120 # default 30
>
>
> > 1) Is there a bug with having MDS daemons acting as standby-replay?
> I can't tell what bug you are referring to based on info below. It does
> seem to work as designed.
>
> Gr. Stefan
>
> --
> | BIT BV http://www.bit.nl/ Kamer van Koophandel 09090351
> | GPG: 0xD14839C6 +31 318 648 688 / [email protected]
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