[lustre-discuss] RDMA too many fragments/timed out - clients slowing entire filesystem performance

Tue Nov 1 16:57:04 PDT 2016

Hi Brian,

You need this patch: http://review.whamcloud.com/#/c/12451.  It has not landed to master yet and is off by default.  To activate it, add this module parameter line to your nodes (all of them):

options ko2iblnd wrq_sge=2

The issue is that something is causing an offset to be introduced to the bulk transfers.  That causes a misalignment of the source and destination fragments.  Due to how the algorithm works, you require twice as many descriptors to the fragments to do the RDMA operation.  So, you are running out of descriptors when you are only halfway done configuring the transfer.  The above patch creates two sets of descriptors so the second set can be utilized in situations like this.  The fix operates on the nodes which are doing the bulk transfers.  Since you can both read and write bulk data, you need the fix on server, clients, and LNet routers (basically, everywhere).

Question: are you using the quotas feature and could it be at or approaching a limit?  There has been some evidence that the quotas feature could be introducing the offset to bulk transfers.

Doug

On Nov 1, 2016, at 4:08 PM, Brian W. Johanson <bjohanso at psc.edu<mailto:bjohanso at psc.edu>> wrote:

Centos 7.2
Lustre 2.8.0
ZFS 0.6.5.5
OPA 10.2.0.0.158

The clients and servers are on the same OPA network, no routing.  Once a client gets in this state, the filesystem performance drops to a faction of what it is capable of.
The client must be rebooted to clear the issue.

I imagine I am missing a bug in jira for this issue, does this look like a known issue?

Pertinent debug messages from the server:

00000800:00020000:34.0:1478026118.277782:0:29892:0:(o2iblnd_cb.c:3109:kiblnd_check_txs_locked()) Timed out tx: active_txs, 4 seconds
00000800:00020000:34.0:1478026118.277785:0:29892:0:(o2iblnd_cb.c:3172:kiblnd_check_conns()) Timed out RDMA with 10.4.119.112 at o2ib (3): c: 112, oc: 0, rc: 66
00000800:00000100:34.0:1478026118.277787:0:29892:0:(o2iblnd_cb.c:1913:kiblnd_close_conn_locked()) Closing conn to 10.4.119.112 at o2ib: error -110(waiting)
00000100:00020000:34.0:1478026118.277844:0:29892:0:(events.c:447:server_bulk_callback()) event type 5, status -103, desc ffff883e8e8bcc00
00000100:00020000:34.0:1478026118.288714:0:29892:0:(events.c:447:server_bulk_callback()) event type 3, status -103, desc ffff883e8e8bcc00
00000100:00020000:34.0:1478026118.299574:0:29892:0:(events.c:447:server_bulk_callback()) event type 5, status -103, desc ffff8810e92e9c00
00000100:00020000:34.0:1478026118.310434:0:29892:0:(events.c:447:server_bulk_callback()) event type 3, status -103, desc ffff8810e92e9c00

And from the client:

00000400:00000100:8.0:1477949860.565777:0:3629:0:(lib-move.c:1489:lnet_parse_put()) Dropping PUT from 12345-10.4.108.81 at o2ib portal 4 match 1549728742532740 offset 0 length 192: 4
00000400:00000100:8.0:1477949860.565782:0:3629:0:(lib-move.c:1489:lnet_parse_put()) Dropping PUT from 12345-10.4.108.81 at o2ib portal 4 match 1549728742532740 offset 0 length 192: 4
00000800:00020000:8.0:1477949860.702666:0:3629:0:(o2iblnd_cb.c:1094:kiblnd_init_rdma()) RDMA has too many fragments for peer 10.4.108.81 at o2ib (32), src idx/frags: 16/27 dst idx/frags: 16/27
00000800:00020000:8.0:1477949860.702667:0:3629:0:(o2iblnd_cb.c:1689:kiblnd_reply()) Can't setup rdma for GET from 10.4.108.81 at o2ib: -90
00000100:00020000:8.0:1477949860.702669:0:3629:0:(events.c:201:client_bulk_callback()) event type 1, status -5, desc ffff880fd5d9bc00
00000800:00020000:8.0:1477949860.816666:0:3629:0:(o2iblnd_cb.c:1094:kiblnd_init_rdma()) RDMA has too many fragments for peer 10.4.108.81 at o2ib (32), src idx/frags: 16/27 dst idx/frags: 16/27
00000800:00020000:8.0:1477949860.816668:0:3629:0:(o2iblnd_cb.c:1689:kiblnd_reply()) Can't setup rdma for GET from 10.4.108.81 at o2ib: -90
00000100:00020000:8.0:1477949860.816669:0:3629:0:(events.c:201:client_bulk_callback()) event type 1, status -5, desc ffff880fd5d9bc00
00000400:00000100:8.0:1477949861.573660:0:3629:0:(lib-move.c:1489:lnet_parse_put()) Dropping PUT from 12345-10.4.108.81 at o2ib portal 4 match 1549728742532740 offset 0 length 192: 4
00000400:00000100:8.0:1477949861.573664:0:3629:0:(lib-move.c:1489:lnet_parse_put()) Dropping PUT from 12345-10.4.108.81 at o2ib portal 4 match 1549728742532740 offset 0 length 192: 4
00000400:00000100:8.0:1477949861.573667:0:3629:0:(lib-move.c:1489:lnet_parse_put()) Dropping PUT from 12345-10.4.108.81 at o2ib portal 4 match 1549728742532740 offset 0 length 192: 4
00000400:00000100:8.0:1477949861.573669:0:3629:0:(lib-move.c:1489:lnet_parse_put()) Dropping PUT from 12345-10.4.108.81 at o2ib portal 4 match 1549728742532740 offset 0 length 192: 4
00000400:00000100:8.0:1477949861.573671:0:3629:0:(lib-move.c:1489:lnet_parse_put()) Dropping PUT from 12345-10.4.108.81 at o2ib portal 4 match 1549728742532740 offset 0 length 192: 4
00000400:00000100:8.0:1477949861.573673:0:3629:0:(lib-move.c:1489:lnet_parse_put()) Dropping PUT from 12345-10.4.108.81 at o2ib portal 4 match 1549728742532740 offset 0 length 192: 4
00000400:00000100:8.0:1477949861.573675:0:3629:0:(lib-move.c:1489:lnet_parse_put()) Dropping PUT from 12345-10.4.108.81 at o2ib portal 4 match 1549728742532740 offset 0 length 192: 4
00000400:00000100:8.0:1477949861.573677:0:3629:0:(lib-move.c:1489:lnet_parse_put()) Dropping PUT from 12345-10.4.108.81 at o2ib portal 4 match 1549728742532740 offset 0 length 192: 4
00000800:00020000:8.0:1477949861.721668:0:3629:0:(o2iblnd_cb.c:1094:kiblnd_init_rdma()) RDMA has too many fragments for peer 10.4.108.81 at o2ib (32), src idx/frags: 16/27 dst idx/frags: 16/27
00000800:00020000:8.0:1477949861.721669:0:3629:0:(o2iblnd_cb.c:1689:kiblnd_reply()) Can't setup rdma for GET from 10.4.108.81 at o2ib: -90
00000100:00020000:8.0:1477949861.721670:0:3629:0:(events.c:201:client_bulk_callback()) event type 1, status -5, desc ffff880fd5d9bc00
00000800:00020000:8.0:1477949861.836668:0:3629:0:(o2iblnd_cb.c:1094:kiblnd_init_rdma()) RDMA has too many fragments for peer 10.4.108.81 at o2ib (32), src idx/frags: 16/27 dst idx/frags: 16/27
00000800:00020000:8.0:1477949861.836669:0:3629:0:(o2iblnd_cb.c:1689:kiblnd_reply()) Can't setup rdma for GET from 10.4.108.81 at o2ib: -90
00000100:00020000:8.0:1477949861.836670:0:3629:0:(events.c:201:client_bulk_callback()) event type 1, status -5, desc ffff880fd5d9bc00
00000800:00020000:8.0:1477949862.061668:0:3629:0:(o2iblnd_cb.c:1094:kiblnd_init_rdma()) RDMA has too many fragments for peer 10.4.108.81 at o2ib (32), src idx/frags: 16/27 dst idx/frags: 16/27
00000800:00020000:8.0:1477949862.061669:0:3629:0:(o2iblnd_cb.c:1689:kiblnd_reply()) Can't setup rdma for GET from 10.4.108.81 at o2ib: -90
00000100:00020000:8.0:1477949862.061670:0:3629:0:(events.c:201:client_bulk_callback()) event type 1, status -5, desc ffff880fd5d9bc00

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