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Currently the farm is suffering from xrootd proxy issue, yet to be identified? Symptoms are high CLOSE_WAIT connection value and xrootd unresponsiveness. Previously it’s been identified that more than ~400 CLOSE_WAIT connections causes xrootd to act erratically.

...

The above nodes how this xrootd proxy issue.

last 24hrs atlas:

...

VO’s running on affected nodes:

  • LHCB (tlhcb006)

  • ATLAS (patls002)

  • NA62 (tna62a001)

  • Biomed (bio045)

  • enmr022

file read timeouts on proxy logs

Nov 16 04:20:34 lcg2631.gridpp.rl.ac.uk docker[1542921]: 231116 04:20:34 92982 XrootdAioTask: async read failed for tlhcb006.2794:170@htcjob4969334_0_slot1_246_pid3678980.ralworker; aio file read timed out /lhcb:buffer/lhcb/MC/2016/SIM/00204827/0008/00204827_00084722_1.sim
Nov 16 04:21:08 lcg2631.gridpp.rl.ac.uk docker[1542921]: 231116 04:21:08 92969 XrootdAioTask: async read failed for tlhcb006.301:77@htcjob5638675_0_slot1_14_pid2226160.ralworker; aio file read timed out /lhcb:buffer/lhcb/MC/2018/SIM/00204836/0009/00204836_00096682_1.sim

futex_wait

Nov 16 06:21:38 lcg2631.gridpp.rl.ac.uk docker[1542921]: 231116 06:21:38 96524 oss_Open_ufs: Unable to reloc FD /xcache/lhcb:buffer/lhcb/MC/2018/SIM/00204818/0008/00204818_00083792_1.sim.cinfo; invalid argument

logs cycle between authentications - no read logs happening

files in cache can be downloaded

Proxy cache discovery

Alex R noticed that cached files from the xrootd-proxy are retrieved successfully, indicating the issue exists with the proxy recalling data from the gateway.

looks like the cache FD cannot be freed?

Nov 15 21:37:07 lcg2631.gridpp.rl.ac.uk docker[1542921]: CEPHSUM-2023-11-15 21:37:07,527-67018-DEBUG-Converted /lhcb:user/lhcb/user/k/kmattiol/GangaJob_350/InputFiles/diracInputFiles_350_dba170b4-0658-444a-bbeb-adb973370624.tgz to lhcb, user/lhcb/user/k/kmattiol/GangaJob_350/InputFiles/diracInputFiles_350_dba170b4-0658-444a-bbeb-adb973370624.tgz
Nov 15 21:37:07 lcg2631.gridpp.rl.ac.uk docker[1542921]: CEPHSUM-2023-11-15 21:37:07,706-67018-DEBUG-Striper: Object size:67108864, Total size:5227299, Num Stripes:1, Last Stripe size:5227299
Nov 15 21:37:07 lcg2631.gridpp.rl.ac.uk docker[1542921]: CEPHSUM-2023-11-15 21:37:07,706-67018-DEBUG-adler32, 1700083974, 1, 0, b'\x00', b'\x04', 4, b'\xf9\xe4\xe9d'
Nov 15 21:37:07 lcg2631.gridpp.rl.ac.uk docker[1542921]: CEPHSUM-2023-11-15 21:37:07,706-67018-DEBUG-Time info: 1700083974, 2023-11-15 21:32:54, 1, 0:00:01, 2023-11-15 21:32:55
Nov 15 21:37:07 lcg2631.gridpp.rl.ac.uk docker[1542921]: CEPHSUM-2023-11-15 21:37:07,706-67018-INFO-XrdCks.adler32: f9e4e964 ; 2023-11-15 21:32:54; 0:00:01; 4
Nov 15 21:37:07 lcg2631.gridpp.rl.ac.uk docker[1542921]: CEPHSUM-2023-11-15 21:37:07,706-67018-INFO-Path:user/lhcb/user/k/kmattiol/GangaJob_350/InputFiles/diracInputFiles_350_dba170b4-0658-444a-bbeb-adb973370624.tgz; From:metadata; Checksum:f9e4e964
Nov 15 21:37:07 lcg2631.gridpp.rl.ac.uk docker[1542921]: CEPHSUM-2023-11-15 21:37:07,728-67018-INFO-Result:Done, pool:lhcb, path:/lhcb:user/lhcb/user/k/kmattiol/GangaJob_350/InputFiles/diracInputFiles_350_dba170b4-0658-444a-bbeb-adb973370624.tgz, checksum:f9e4e964, time_s:0.20102, filesize_bytes:5227299, source:metadata, exit_code:0, srccks:N/A
-----READ FINISHED---------

Nov 16 09:59:34 lcg2631.gridpp.rl.ac.uk docker[1542921]: 231116 09:59:34 102659 acc_Audit: xrootd.102663:6647@localhost grant gsi 0495af69.0@localhost read /lhcb:user/lhcb/user/k/kmattiol/GangaJob_350/InputFiles/diracInputFiles_350_dba170b4-0658-444a-bbeb-adb973370624.tgz
Nov 16 09:59:34 lcg2631.gridpp.rl.ac.uk docker[1542921]: 231116 09:59:34 102659 oss_Open_ufs: Unable to reloc FD /xcache/lhcb:user/lhcb/user/k/kmattiol/GangaJob_350/InputFiles/diracInputFiles_350_dba170b4-0658-444a-bbeb-adb973370624.tgz.cinfo; invalid argument
Nov 16 09:59:34 lcg2631.gridpp.rl.ac.uk docker[1542921]: 231116 09:59:34 102659 oss_Open_ufs: Unable to reloc FD /xcache/lhcb:user/lhcb/user/k/kmattiol/GangaJob_350/InputFiles/diracInputFiles_350_dba170b4-0658-444a-bbeb-adb973370624.tgz; invalid argument
Nov 16 09:59:34 lcg2631.gridpp.rl.ac.uk docker[1542921]: 231116 09:59:34 102659 oss_Open_ufs: Unable to reloc FD /xcache/lhcb:user/lhcb/user/k/kmattiol/GangaJob_350/InputFiles/diracInputFiles_350_dba170b4-0658-444a-bbeb-adb973370624.tgz.cinfo; invalid argument

---after manually clearing file from cache and attempting to read----

Nov 16 10:12:13 lcg2631.gridpp.rl.ac.uk docker[1542921]: 231116 10:12:13 103058 XrootdAioTask: aioR overdue 8 inflight requests for xrootd.103062:6877@localhost /lhcb:user/lhcb/user/k/kmattiol/GangaJob_350/InputFiles/diracInputFiles_350_dba170b4-0658-444a-bbeb-adb973370624.tgz


Tcpdump shows that gateway for new connections closes the channes on its side for some reason immediately after connection establishment:

Code Block
10:31:09.812402 IP (tos 0x0, ttl 64, id 55828, offset 0, flags [DF], proto TCP (6), length 60)
    172.28.1.1.36580 > 172.28.1.2.nicelink: Flags [S], cksum 0x5a6a (incorrect -> 0x539f), seq 1788468839, win 64240, options [mss 1460,sackOK,TS val 2782928166 ecr 0,nop,wscale 8], length 0
10:31:09.812498 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 60)
    172.28.1.2.nicelink > 172.28.1.1.36580: Flags [S.], cksum 0x5a6a (incorrect -> 0x3470), seq 1456405645, ack 1788468840, win 65160, options [mss 1460,sackOK,TS val 4249275106 ecr 2782928166,nop,wscale 8], length 0
10:31:09.812515 IP (tos 0x0, ttl 64, id 55829, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.1.36580 > 172.28.1.2.nicelink: Flags [.], cksum 0x5a62 (incorrect -> 0x60cb), seq 1, ack 1, win 251, options [nop,nop,TS val 2782928166 ecr 4249275106], length 0
10:31:39.842286 IP (tos 0x0, ttl 64, id 51510, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.2.nicelink > 172.28.1.1.36580: Flags [F.], cksum 0x5a62 (incorrect -> 0xeb77), seq 1, ack 1, win 255, options [nop,nop,TS val 4249305136 ecr 2782928166], length 0
10:31:39.843151 IP (tos 0x0, ttl 64, id 55830, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.1.36580 > 172.28.1.2.nicelink: Flags [.], cksum 0x5a62 (incorrect -> 0x762c), seq 1, ack 2, win 251, options [nop,nop,TS val 2782958197 ecr 4249305136], length 0


Established connections show zero window size on the proxy side:

Code Block
10:32:16.344156 IP (tos 0x0, ttl 64, id 32198, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.2.nicelink > 172.28.1.1.39048: Flags [.], cksum 0x5a62 (incorrect -> 0x1d5c), seq 3536181248, ack 500688318, win 255, options [nop,nop,TS val 4249341638 ecr 2782871820], length 0
10:32:16.344171 IP (tos 0x0, ttl 64, id 7615, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.1.39048 > 172.28.1.2.nicelink: Flags [.], cksum 0x5a62 (incorrect -> 0xa608), seq 1, ack 1, win 0, options [nop,nop,TS val 2782994698 ecr 4228343896], length 0
10:34:19.226332 IP (tos 0x0, ttl 64, id 32199, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.2.nicelink > 172.28.1.1.39048: Flags [.], cksum 0x5a62 (incorrect -> 0x5d5b), seq 0, ack 1, win 255, options [nop,nop,TS val 4249464517 ecr 2782994698], length 0
10:34:19.226359 IP (tos 0x0, ttl 64, id 7616, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.1.39048 > 172.28.1.2.nicelink: Flags [.], cksum 0x5a62 (incorrect -> 0xc604), seq 1, ack 1, win 0, options [nop,nop,TS val 2783117580 ecr 4228343896], length 0
10:36:22.104834 IP (tos 0x0, ttl 64, id 32200, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.2.nicelink > 172.28.1.1.39048: Flags [.], cksum 0x5a62 (incorrect -> 0x9d55), seq 0, ack 1, win 255, options [nop,nop,TS val 4249587397 ecr 2783117580], length 0
10:36:22.104857 IP (tos 0x0, ttl 64, id 7617, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.1.39048 > 172.28.1.2.nicelink: Flags [.], cksum 0x5a62 (incorrect -> 0xe604), seq 1, ack 1, win 0, options [nop,nop,TS val 2783240458 ecr 4228343896], length 0
10:38:24.985069 IP (tos 0x0, ttl 64, id 32201, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.2.nicelink > 172.28.1.1.39048: Flags [.], cksum 0x5a62 (incorrect -> 0xdd52), seq 0, ack 1, win 255, options [nop,nop,TS val 4249710278 ecr 2783240458], length 0
10:38:24.985093 IP (tos 0x0, ttl 64, id 7618, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.1.39048 > 172.28.1.2.nicelink: Flags [.], cksum 0x5a62 (incorrect -> 0x0603), seq 1, ack 1, win 0, options [nop,nop,TS val 2783363338 ecr 4228343896], length 0
10:40:27.865005 IP (tos 0x0, ttl 64, id 32202, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.2.nicelink > 172.28.1.1.39048: Flags [.], cksum 0x5a62 (incorrect -> 0x1d50), seq 0, ack 1, win 255, options [nop,nop,TS val 4249833157 ecr 2783363338], length 0
10:40:27.865025 IP (tos 0x0, ttl 64, id 7619, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.1.39048 > 172.28.1.2.nicelink: Flags [.], cksum 0x5a62 (incorrect -> 0x2601), seq 1, ack 1, win 0, options [nop,nop,TS val 2783486218 ecr 4228343896], length 0
10:42:30.744155 IP (tos 0x0, ttl 64, id 32203, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.2.nicelink > 172.28.1.1.39048: Flags [.], cksum 0x5a62 (incorrect -> 0x5d4b), seq 0, ack 1, win 255, options [nop,nop,TS val 4249956038 ecr 2783486218], length 0
10:42:30.744167 IP (tos 0x0, ttl 64, id 7620, offset 0, flags [DF], proto TCP (6), length 52)
    172.28.1.1.39048 > 172.28.1.2.nicelink: Flags [.], cksum 0x5a62 (incorrect -> 0x45ff), seq 1, ack 1, win 0, options [nop,nop,TS val 2783609098 ecr 4228343896], length 0