[LU-5724] IR recovery doesn't behave properly with Lustre 2.5

• Type: Bug
• Resolution: Duplicate
• Priority: Critical
• Affects Version/s: Lustre 2.5.3
• Labels: llnl ornl p4o
• Environment: MDS server running RHEL6.5 running ORNL 2.5.3 branch with about 12 patches.
• Severity: 2
• Assignee: Hongchao Zhang
• Reporter: James A Simmons

Description

Today we experienced a hardware failure with our MDS. The MDS rebooted and then came back. We restarted the MDS but IR behaved strangely. Four clients got evicted but when the timer to completion got down to zero IR restarted all over again. Then once it got to the 700 second range the timer starting to go up. It did this a few times before letting the timer running out. Once the timer did finally get to zero the recovery state was reported as still being in recovery. It removed this way for several more minutes before finally being in a recovered state. In all it toke 54 minutes to recover.

Issue Links

• duplicates: LU-4119 recovery time hard doesn't limit recovery duration
• is related to: LU-5079 conf-sanity test_47 timeout

Comments

[Jian Yu]

With the patch for LU-4119, the recovery issue did not occur at small scale testing in ORNL. Large scale testing will be performed.

[Hongchao Zhang]

Is the failover mode the same for both tests at Dec 31, 2014 and at Jan 14, 2015, which is there is a separated node
only running MGS connected by MDS, OSSs and the clients nodes, and the MDS and OSSs are failed over together?

[James A Simmons]

No the MGS is left up. We failed over the MDS and OSS together.

[Hongchao Zhang]

Are both MGS and MDS failed over in this test?

the IR status will be set IR_STARTUP after MGS is started and will be changed to IR_FULL after "ir_timeout" seconds
(default is OBD_IR_MGS_TIMEOUT = "4*obd_timeout"). the target(MDT or OST) registered to MGS will only be marked as
"LDD_F_IR_CAPABLE" if the IR status is IR_FULL, and "IR" will be printed as "DISABLED" in this case.

for the client side, the imperative_recovery will be marked as "Enabled" if the connection with the server supports recovery
(imp->imp_connect_data & OBD_CONNECT_IMP_RECOV == TRUE).

[James A Simmons]

Testing failover and we see with just the MDS being failed over:

very 1.0s: cat recovery_status Wed Jan 14 14:11:11 2015

status: COMPLETE
recovery_start: 1421262582
recovery_duration: 60
completed_clients: 82/82
replayed_requests: 0
last_transno: 90194315377
VBR: DISABLED
IR: DISABLED

All clients are 2.5+ so there should be no reason that IR is disabled. Can you report this problem on your side?

On the MGS we see during failover.

root@atlas-tds-mds1 MGC10.36.226.79@o2ib]# cat ir_state
imperative_recovery: ENABLED
client_state:

• { client: atlastds-MDT0000, nidtbl_version: 957 }

[Hongchao Zhang]

sorry for misunderstanding! Yes, Lustre supports both MDT and OSS to fail over.

[Jian Yu]

In Lustre test suite, the following sub-tests in insanity.sh test failing MDS and OSS at the same time:

run_test 2 "Second Failure Mode: MDS/OST `date`"
run_test 4 "Fourth Failure Mode: OST/MDS `date`"

The basic test steps for sub-test 2 are:

fail MDS
fail OSS
start OSS
start MDS

And the basic test steps for sub-test 4 are:

fail OSS
fail MDS
start OSS
start MDS

Here is the insanity test report for Lustre b2_5 build #107: https://testing.hpdd.intel.com/test_sets/bfd812b0-8a4d-11e4-a10b-5254006e85c2

[Oleg Drokin]

I think what HongChao tries to say is that when MDS and OST both go down, then since MDS is a client of OST, the OST recovery can never complete because of the missing client.

But on the other hand we took two steps to help this. First, MDS client UUID should be always the same, so even after restart it still should be allowed to reconnect as the old known client (this is assuming it actually got up and into reconecting state in time for OST recovery. if your MDS takes ages to reboot, for example, it might miss this window, esp. if it's a shortened window thanks to IR).

Second, we have VBR to deal with missing clients during recovery, which is esp. easy with MDT client, since it never has any outstanding uncommitted transactions to replay.

[James A Simmons]

We have had success before with MDS+OSS failing over at the same time in the past. We really like to have that functionality restored.

[Hongchao Zhang]

Is the client (rhea513, 10.38.146.45) the Lustre client connected to "atlastds"?
this client mounted at "Dec 29 12:55:33", but umounted at "Dec 29 14:04:54", but the MDT failed over at "Dec 29 13:55:12" and the Lustre was started only at "Dec 29 14:26:55".

at Client (rhea513, 10.38.146.45)

 
Dec 29 12:55:33 rhea513.ccs.ornl.gov kernel: Lustre: client wants to enable acl, but mdt not!
Dec 29 12:55:33 rhea513.ccs.ornl.gov kernel: Lustre: Layout lock feature supported.
Dec 29 12:55:33 rhea513.ccs.ornl.gov kernel: Lustre: Mounted atlastds-client
Dec 29 14:00:00 rhea513.ccs.ornl.gov kernel: Lustre: 5367:0:(client.c:1940:ptlrpc_expire_one_request()) @@@ Request sent has timed out for slow reply: [sent 1419879033/real 1419879033]  req@ffff881000328000 x1487757986577588/t0(0) o400->atlastds-OST0033-osc-ffff880820a28c00@10.36.226.67@o2ib:28/4 lens 224/224 e 0 to 1 dl 1419879600 ref 1 fl Rpc:XN/0/ffffffff rc 0/-1
Dec 29 14:00:00 rhea513.ccs.ornl.gov kernel: Lustre: atlastds-OST0023-osc-ffff880820a28c00: Connection to atlastds-OST0023 (at 10.36.226.67@o2ib) was lost; in progress operations using this service will wait for recovery to complete
Dec 29 14:00:00 rhea513.ccs.ornl.gov kernel: Lustre: atlastds-OST002e-osc-ffff880820a28c00: Connection to atlastds-OST002e (at 10.36.226.70@o2ib) was lost; in progress operations using this service will wait for recovery to complete
Dec 29 14:00:00 rhea513.ccs.ornl.gov kernel: LustreError: 166-1: MGC10.36.226.79@o2ib: Connection to MGS (at 10.36.226.79@o2ib) was lost; in progress operations using this service will fail
Dec 29 14:00:00 rhea513.ccs.ornl.gov kernel: Lustre: 5367:0:(client.c:1940:ptlrpc_expire_one_request()) Skipped 52 previous similar messages
Dec 29 14:04:40 rhea513.ccs.ornl.gov kernel: Lustre: 5358:0:(client.c:1940:ptlrpc_expire_one_request()) @@@ Request sent has timed out for slow reply: [sent 1419879600/real 1419879600]  req@ffff88102a64b800 x1487757986596960/t0(0) o8->atlastds-OST0033-osc-ffff880820a28c00@10.36.226.67@o2ib:28/4 lens 400/544 e 0 to 1 dl 1419879880 ref 1 fl Rpc:XN/0/ffffffff rc 0/-1
Dec 29 14:04:40 rhea513.ccs.ornl.gov kernel: Lustre: 5358:0:(client.c:1940:ptlrpc_expire_one_request()) Skipped 1 previous similar message
Dec 29 14:04:54 rhea513.ccs.ornl.gov kernel: Lustre: Unmounted atlastds-client

at MDT (10.36.226.69)

Dec 29 13:56:16 atlas-tds-oss6.ccs.ornl.gov kernel: [  117.814766]  sdbd:
Dec 29 13:56:16 atlas-tds-oss6.ccs.ornl.gov kernel: [  117.814952] sd 7:0:0:98: [sdaj] Attached SCSI disk
Dec 29 13:56:16 atlas-tds-oss6.ccs.ornl.gov kernel: [  117.835086]  unknown partition table
Dec 29 13:56:16 atlas-tds-oss6.ccs.ornl.gov kernel: [  117.845364]  unknown partition table
Dec 29 13:56:16 atlas-tds-oss6.ccs.ornl.gov kernel: [  117.864189] sd 6:0:0:71: [sdau] Attached SCSI disk
Dec 29 13:56:16 atlas-tds-oss6.ccs.ornl.gov kernel: [  117.864257] sd 6:0:0:101: [sdbd] Attached SCSI disk
Dec 29 13:56:16 atlas-tds-oss6.ccs.ornl.gov kernel: [  117.970252] device-mapper: multipath round-robin: version 1.0.0 loaded
Dec 29 14:26:55 atlas-tds-oss6.ccs.ornl.gov kernel: [ 1957.955421] LNet: HW CPU cores: 16, npartitions: 4
Dec 29 14:26:55 atlas-tds-oss6.ccs.ornl.gov kernel: [ 1957.963523] alg: No test for crc32 (crc32-table)
Dec 29 14:26:55 atlas-tds-oss6.ccs.ornl.gov kernel: [ 1957.977845] alg: No test for adler32 (adler32-zlib)
Dec 29 14:26:55 atlas-tds-oss6.ccs.ornl.gov kernel: [ 1957.988788] alg: No test for crc32 (crc32-pclmul)
Dec 29 14:26:59 atlas-tds-oss6.ccs.ornl.gov kernel: [ 1962.022800] padlock: VIA PadLock Hash Engine not detected.
Dec 29 14:27:04 atlas-tds-oss6.ccs.ornl.gov kernel: [ 1966.277906] LNet: Added LNI 10.36.226.69@o2ib [63/2560/0/180]
Dec 29 14:27:04 atlas-tds-oss6.ccs.ornl.gov kernel: [ 1966.814213] LNet: Added LNI 10.36.226.69@o2ib200 [63/2560/0/180]
Dec 29 14:27:04 atlas-tds-oss6.ccs.ornl.gov kernel: [ 1967.054096] Lustre: Lustre: Build Version: 2.5.3-g6158f83-CHANGED-2.6.32-431.29.2.el6.atlas.x86_64

btw, in this failover test of both MDT and OSS was rebooted, and recovery will be slow for the OSSs will wait time to evict the client from MDT, which won't reconnect to recover.
and Lustre seems not to support both MDS and OSS to failover, IIRC.

[James A Simmons]

Here are the kern logs for a client and a router. If you want the logs for all the clients let me know.