Bug 1636291 - [SNAPSHOT]: with brick multiplexing, snapshot restore will make glusterd send wrong volfile
Summary: [SNAPSHOT]: with brick multiplexing, snapshot restore will make glusterd send...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Gluster Storage
Classification: Red Hat Storage
Component: snapshot
Version: rhgs-3.4
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: ---
: RHGS 3.4.z Batch Update 2
Assignee: Raghavendra Bhat
QA Contact: Upasana
URL:
Whiteboard:
Depends On: 1635050 1636162 1636218 1647165
Blocks:
TreeView+ depends on / blocked
 
Reported: 2018-10-05 02:13 UTC by Atin Mukherjee
Modified: 2023-09-14 04:39 UTC (History)
11 users (show)

Fixed In Version: glusterfs-3.12.2-27
Doc Type: Bug Fix
Doc Text:
Previously, when brick multiplexing was enabled and a snapshot was being restored, glusterd would be sent the volume file of a client to the snapshot brick instead of sending the brick volume file. As a consequence, snapshot bricks were created based on the client volume files leading to unavailability of the snapshot data to applications. This update ensures that correct volume file is used while creating snapshot when brick multiplexing is enabled.
Clone Of: 1636162
Environment:
Last Closed: 2018-12-17 17:07:11 UTC
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2018:3827 0 None None None 2018-12-17 17:07:27 UTC

Description Atin Mukherjee 2018-10-05 02:13:25 UTC 
+++ This bug was initially created as a clone of Bug #1636162 +++

+++ This bug was initially created as a clone of Bug #1635050 +++

Description of problem:

With brick multiplexing, when a snapshot restore is done, it leads to a snapshot brick getting the client volume file for the corresponding snapshot volume instead of the correct brick volume file.


[2018-09-28 23:34:10.405953] I [glusterfsd-mgmt.c:279:glusterfs_handle_terminate] 0-glusterfs: detaching not-only child /run/gluster/snaps/1534bc2e092341d7bb7d940e9728c3ca/brick1/mirror
[2018-09-28 23:34:10.406009] I [glusterfsd-mgmt.c:279:glusterfs_handle_terminate] 0-glusterfs: detaching not-only child /run/gluster/snaps/1534bc2e092341d7bb7d940e9728c3ca/brick2/mirror

The above 2 lines indicate that it is a brick process. Because of restore, the original snapshot volume's bricks are stopped leading to a detach of the bricks happening which is logged above.


[2018-09-28 23:34:10.407276] E [rpcsvc.c:1542:rpcsvc_program_unregister_portmap] 0-rpc-service: Could not unregister with portmap
[2018-09-28 23:34:10.407276] E [rpcsvc.c:1542:rpcsvc_program_unregister_portmap] 0-rpc-service: Could not unregister with portmap
[2018-09-28 23:34:10.407299] E [rpcsvc.c:1670:rpcsvc_program_unregister] 0-rpc-service: portmap unregistration of program failed
[2018-09-28 23:34:10.407310] E [rpcsvc.c:1670:rpcsvc_program_unregister] 0-rpc-service: portmap unregistration of program failed
[2018-09-28 23:34:10.407319] E [rpcsvc.c:1720:rpcsvc_program_unregister] 0-rpc-service: Program unregistration failed: GlusterFS Changelog, Num: 1885957735, Ver: 1, Port: 0
[2018-09-28 23:34:10.407323] E [rpcsvc.c:1720:rpcsvc_program_unregister] 0-rpc-service: Program unregistration failed: GlusterFS Changelog, Num: 1885957735, Ver: 1, Port: 0
[2018-09-28 23:34:10.409365] I [barrier.c:665:fini] 0-1534bc2e092341d7bb7d940e9728c3ca-barrier: Disabling barriering and dequeuing all the queued fops
[2018-09-28 23:34:10.409382] I [barrier.c:665:fini] 0-1534bc2e092341d7bb7d940e9728c3ca-barrier: Disabling barriering and dequeuing all the queued fops
[2018-09-28 23:34:10.413063] I [io-stats.c:3937:fini] 0-1534bc2e092341d7bb7d940e9728c3ca-io-stats: io-stats translator unloaded
[2018-09-28 23:34:10.413151] I [rpcsvc.c:2054:rpcsvc_spawn_threads] 0-rpc-service: terminating 1 threads for program 'GlusterFS 4.x v1'
[2018-09-28 23:34:10.413178] I [rpcsvc.c:2054:rpcsvc_spawn_threads] 0-rpc-service: terminating 1 threads for program 'GlusterFS 3.3'
[2018-09-28 23:34:10.413182] I [rpcsvc.c:1993:rpcsvc_request_handler] 0-rpc-service: program 'GlusterFS 4.x v1' thread terminated; total count:3
[2018-09-28 23:34:10.413195] I [rpcsvc.c:1993:rpcsvc_request_handler] 0-rpc-service: program 'GlusterFS 3.3' thread terminated; total count:3
[2018-09-28 23:34:10.413700] I [io-stats.c:3937:fini] 0-1534bc2e092341d7bb7d940e9728c3ca-io-stats: io-stats translator unloaded
[2018-09-28 23:34:10.413775] I [rpcsvc.c:2054:rpcsvc_spawn_threads] 0-rpc-service: terminating 1 threads for program 'GlusterFS 4.x v1'
[2018-09-28 23:34:10.413786] I [rpcsvc.c:2054:rpcsvc_spawn_threads] 0-rpc-service: terminating 1 threads for program 'GlusterFS 3.3'
[2018-09-28 23:34:10.413805] I [rpcsvc.c:1993:rpcsvc_request_handler] 0-rpc-service: program 'GlusterFS 4.x v1' thread terminated; total count:2
[2018-09-28 23:34:10.413807] I [rpcsvc.c:1993:rpcsvc_request_handler] 0-rpc-service: program 'GlusterFS 3.3' thread terminated; total count:2
[2018-09-28 23:34:10.923188] I [glusterfsd-mgmt.c:58:mgmt_cbk_spec] 0-mgmt: Volume file changed
[2018-09-28 23:34:10.923350] I [MSGID: 101191] [event-epoll.c:653:event_dispatch_epoll_worker] 0-epoll: Exited thread with index 3
[2018-09-28 23:34:11.031917] I [MSGID: 101191] [event-epoll.c:653:event_dispatch_epoll_worker] 0-epoll: Exited thread with index 4
[2018-09-28 23:34:57.645690] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/protocol/client.so: undefined symbol: xlator_api. Fall back
 to old symbols
[2018-09-28 23:34:57.646288] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/cluster/replicate.so: undefined symbol: xlator_api. Fall ba
ck to old symbols
[2018-09-28 23:34:57.646714] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/features/read-only.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.646929] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/performance/write-behind.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.647103] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/performance/read-ahead.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.647274] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/performance/readdir-ahead.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.647470] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/performance/io-cache.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.647817] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/performance/open-behind.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.648021] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/debug/io-stats.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.649370] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/cluster/replicate.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.649654] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/features/read-only.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.649858] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/performance/write-behind.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.650027] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/performance/read-ahead.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.650192] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/performance/readdir-ahead.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.650381] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/performance/io-cache.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.650716] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/performance/open-behind.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.650914] I [MSGID: 101097] [xlator.c:341:xlator_dynload_newway] 0-xlator: dlsym(xlator_api) on /usr/local/lib/glusterfs/6dev/xlator/debug/io-stats.so: undefined symbol: xlator_api. Fall back to old symbols
[2018-09-28 23:34:57.652878] W [MSGID: 101174] [graph.c:397:_log_if_unknown_option] 7-mirror-client-1: option 'transport.address-family' is not recognized
[2018-09-28 23:34:57.652911] W [MSGID: 101174] [graph.c:397:_log_if_unknown_option] 7-mirror-client-1: option 'transport.tcp-user-timeout' is not recognized
[2018-09-28 23:34:57.652919] W [MSGID: 101174] [graph.c:397:_log_if_unknown_option] 7-mirror-client-1: option 'transport.socket.keepalive-time' is not recognized
[2018-09-28 23:34:57.652927] W [MSGID: 101174] [graph.c:397:_log_if_unknown_option] 7-mirror-client-1: option 'transport.socket.keepalive-interval' is not recognized
[2018-09-28 23:34:57.652934] W [MSGID: 101174] [graph.c:397:_log_if_unknown_option] 7-mirror-client-1: option 'transport.socket.keepalive-count' is not recognized
[2018-09-28 23:34:57.652946] W [MSGID: 101174] [graph.c:397:_log_if_unknown_option] 7-mirror-client-0: option 'transport.address-family' is not recognized
[2018-09-28 23:34:57.652954] W [MSGID: 101174] [graph.c:397:_log_if_unknown_option] 7-mirror-client-0: option 'transport.tcp-user-timeout' is not recognized
[2018-09-28 23:34:57.652962] W [MSGID: 101174] [graph.c:397:_log_if_unknown_option] 7-mirror-client-0: option 'transport.socket.keepalive-time' is not recognized
[2018-09-28 23:34:57.652969] W [MSGID: 101174] [graph.c:397:_log_if_unknown_option] 7-mirror-client-0: option 'transport.socket.keepalive-interval' is not recognized
[2018-09-28 23:34:57.652976] W [MSGID: 101174] [graph.c:397:_log_if_unknown_option] 7-mirror-client-0: option 'transport.socket.keepalive-count' is not recognized
[2018-09-28 23:34:57.683329] I [MSGID: 114020] [client.c:2354:notify] 7-mirror-client-1: parent translators are ready, attempting connect on transport
Final graph:
+------------------------------------------------------------------------------+
  1: volume mirror-client-0
  2:     type protocol/client
  3:     option ping-timeout 42
  4:     option remote-host workspace
  5:     option remote-subvolume /run/gluster/snaps/31717a7458a543dca4bffc8e6b1017cc/brick1/mirror
  6:     option transport-type socket
  7:     option transport.address-family inet
  8:     option username 8b527b11-a2e6-45e3-a12a-99b46dc636ab
  9:     option password 01f72c35-9b3a-47b3-852b-95bdb481e66a
 10:     option transport.tcp-user-timeout 0
 11:     option transport.socket.keepalive-time 20
 12:     option transport.socket.keepalive-interval 2
 13:     option transport.socket.keepalive-count 9
 14:     option send-gids true
 15: end-volume
 16:  
 17: volume mirror-client-1
 18:     type protocol/client
 19:     option ping-timeout 42
 20:     option remote-host workspace
 21:     option remote-subvolume /run/gluster/snaps/31717a7458a543dca4bffc8e6b1017cc/brick2/mirror
 22:     option transport-type socket
 23:     option transport.address-family inet
 24:     option username 8b527b11-a2e6-45e3-a12a-99b46dc636ab
 25:     option password 01f72c35-9b3a-47b3-852b-95bdb481e66a
 26:     option transport.tcp-user-timeout 0
 27:     option transport.socket.keepalive-time 20
 28:     option transport.socket.keepalive-interval 2
 29:     option transport.socket.keepalive-count 9
 30:     option send-gids true
 31: end-volume
 32:  
 33: volume 31717a7458a543dca4bffc8e6b1017cc-replicate-0
 34:     type cluster/replicate
 35:     option afr-pending-xattr mirror-client-0,mirror-client-1
 36:     option use-compound-fops off
 37:     subvolumes mirror-client-0 mirror-client-1
 38: end-volume
 39:
 40: volume 31717a7458a543dca4bffc8e6b1017cc-dht
 41:     type cluster/distribute
 42:     option lock-migration off
 43:     option force-migration off
 44:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-replicate-0
 45: end-volume
 46:  
 47: volume 31717a7458a543dca4bffc8e6b1017cc-read-only
 48:     type features/read-only
 49:     option read-only on
 50:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-dht
 51: end-volume
 52:  
 53: volume 31717a7458a543dca4bffc8e6b1017cc-write-behind
 54:     type performance/write-behind
 55:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-read-only
 56: end-volume
 57:  
 58: volume 31717a7458a543dca4bffc8e6b1017cc-read-ahead
 59:     type performance/read-ahead
 60:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-write-behind
 61: end-volume
 62:  
 63: volume 31717a7458a543dca4bffc8e6b1017cc-readdir-ahead
 64:     type performance/readdir-ahead
 65:     option parallel-readdir off
 66:     option rda-request-size 131072
 67:     option rda-cache-limit 10MB
 68:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-read-ahead
 69: end-volume
 70:  
 71: volume 31717a7458a543dca4bffc8e6b1017cc-io-cache
 72:     type performance/io-cache
 73:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-readdir-ahead
 74: end-volume
 75:  
 76: volume 31717a7458a543dca4bffc8e6b1017cc-quick-read
 77:     type performance/quick-read
 78:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-io-cache
 79: end-volume
 80:  
 81: volume 31717a7458a543dca4bffc8e6b1017cc-open-behind
 82:     type performance/open-behind
 83:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-quick-read
 84: end-volume
 85:  
 86: volume 31717a7458a543dca4bffc8e6b1017cc-md-cache
 87:     type performance/md-cache
 88:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-open-behind
 89: end-volume
 90:
 91: volume 31717a7458a543dca4bffc8e6b1017cc
 92:     type debug/io-stats
 93:     option log-level INFO
 94:     option latency-measurement off
 95:     option count-fop-hits off
 96:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-md-cache
 97: end-volume
 98:  
+------------------------------------------------------------------------------+


Version-Release number of selected component (if applicable):


How reproducible:
Always

Steps to Reproduce:
1. Create couple of snapshots for a gluster volume
2. Then do a snapshot restore
3.

Actual results:
Client volfile is sent to the snapshot brick.

Expected results:
Actual brick volfile should be sent.

Additional info:

--- Additional comment from Worker Ant on 2018-10-01 18:03:32 EDT ---

REVIEW: https://review.gluster.org/21314 (mgmt/glusterd: use proper path to the volfile) posted (#1) for review on master by Raghavendra Bhat

--- Additional comment from Mohammed Rafi KC on 2018-10-03 07:04:01 EDT ---

I tried to reproduce the issue. I wasn't able to hit with the given steps to reproduce. Am I missing anything here?

--- Additional comment from Raghavendra Bhat on 2018-10-03 08:47:30 EDT ---


Rafi, once you do snapshot restore, please check the log file of the multiplexed snapshot brick. It prints the client volfile. IMO it should not happen. In fact, due to another memory corruption bug, the brick process crashed after it got the client volfile (the corruption bug is in the client stack).

--- Additional comment from Worker Ant on 2018-10-04 01:03:07 EDT ---

REVIEW: https://review.gluster.org/21314 (mgmt/glusterd: use proper path to the volfile) posted (#4) for review on master by Atin Mukherjee

--- Additional comment from Worker Ant on 2018-10-04 11:39:44 EDT ---

REVIEW: https://review.gluster.org/21347 (mgmt/glusterd: use proper path to the volfile) posted (#1) for review on release-5 by Raghavendra Bhat
Comment 2 Atin Mukherjee 2018-10-05 02:14:49 UTC 
upstream patch : https://review.gluster.org/21314
Comment 9 Raghavendra Bhat 2018-11-19 13:42:51 UTC 
The steps mentioned in comment #6 are correct. A volume file is one which is used by gluster processes to define their behavior (as in whether it is a brick, a client etc). A typical client volume file looks like this.


+------------------------------------------------------------------------------+
  1: volume mirror-client-0
  2:     type protocol/client
  3:     option ping-timeout 42
  4:     option remote-host workspace
  5:     option remote-subvolume /run/gluster/snaps/31717a7458a543dca4bffc8e6b1017cc/brick1/mirror
  6:     option transport-type socket
  7:     option transport.address-family inet
  8:     option username 8b527b11-a2e6-45e3-a12a-99b46dc636ab
  9:     option password 01f72c35-9b3a-47b3-852b-95bdb481e66a
 10:     option transport.tcp-user-timeout 0
 11:     option transport.socket.keepalive-time 20
 12:     option transport.socket.keepalive-interval 2
 13:     option transport.socket.keepalive-count 9
 14:     option send-gids true
 15: end-volume
 16:  
 17: volume mirror-client-1
 18:     type protocol/client
 19:     option ping-timeout 42
 20:     option remote-host workspace
 21:     option remote-subvolume /run/gluster/snaps/31717a7458a543dca4bffc8e6b1017cc/brick2/mirror
 22:     option transport-type socket
 23:     option transport.address-family inet
 24:     option username 8b527b11-a2e6-45e3-a12a-99b46dc636ab
 25:     option password 01f72c35-9b3a-47b3-852b-95bdb481e66a
 26:     option transport.tcp-user-timeout 0
 27:     option transport.socket.keepalive-time 20
 28:     option transport.socket.keepalive-interval 2
 29:     option transport.socket.keepalive-count 9
 30:     option send-gids true
 31: end-volume
 32:  
 33: volume 31717a7458a543dca4bffc8e6b1017cc-replicate-0
 34:     type cluster/replicate
 35:     option afr-pending-xattr mirror-client-0,mirror-client-1
 36:     option use-compound-fops off
 37:     subvolumes mirror-client-0 mirror-client-1
 38: end-volume
 39:
 40: volume 31717a7458a543dca4bffc8e6b1017cc-dht
 41:     type cluster/distribute
 42:     option lock-migration off
 43:     option force-migration off
 44:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-replicate-0
 45: end-volume
 46:  
 47: volume 31717a7458a543dca4bffc8e6b1017cc-read-only
 48:     type features/read-only
 49:     option read-only on
 50:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-dht
 51: end-volume
 52:  
 53: volume 31717a7458a543dca4bffc8e6b1017cc-write-behind
 54:     type performance/write-behind
 55:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-read-only
 56: end-volume
 57:  
 58: volume 31717a7458a543dca4bffc8e6b1017cc-read-ahead
 59:     type performance/read-ahead
 60:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-write-behind
 61: end-volume
 62:  
 63: volume 31717a7458a543dca4bffc8e6b1017cc-readdir-ahead
 64:     type performance/readdir-ahead
 65:     option parallel-readdir off
 66:     option rda-request-size 131072
 67:     option rda-cache-limit 10MB
 68:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-read-ahead
 69: end-volume
 70:  
 71: volume 31717a7458a543dca4bffc8e6b1017cc-io-cache
 72:     type performance/io-cache
 73:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-readdir-ahead
 74: end-volume
 75:  
 76: volume 31717a7458a543dca4bffc8e6b1017cc-quick-read
 77:     type performance/quick-read
 78:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-io-cache
 79: end-volume
 80:  
 81: volume 31717a7458a543dca4bffc8e6b1017cc-open-behind
 82:     type performance/open-behind
 83:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-quick-read
 84: end-volume
 85:  
 86: volume 31717a7458a543dca4bffc8e6b1017cc-md-cache
 87:     type performance/md-cache
 88:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-open-behind
 89: end-volume
 90:
 91: volume 31717a7458a543dca4bffc8e6b1017cc
 92:     type debug/io-stats
 93:     option log-level INFO
 94:     option latency-measurement off
 95:     option count-fop-hits off
 96:     subvolumes 31717a7458a543dca4bffc8e6b1017cc-md-cache
 97: end-volume
 98:  
+------------------------------------------------------------------------------+

Let me give some information which might help you in validating.

Below is the description of one of the xlators in the volume file namely protocol/client. The presence of this xlator means a the process whose logfile had this volfile printed (full volfile printed above, this is just one of the xlators described by the volfile) acted like a client.


 1: volume mirror-client-0
  2:     type protocol/client  =========> This is a client xlator. Type says it
  3:     option ping-timeout 42
  4:     option remote-host workspace
  5:     option remote-subvolume /run/gluster/snaps/31717a7458a543dca4bffc8e6b1017cc/brick1/mirror
  6:     option transport-type socket
  7:     option transport.address-family inet
  8:     option username 8b527b11-a2e6-45e3-a12a-99b46dc636ab
  9:     option password 01f72c35-9b3a-47b3-852b-95bdb481e66a
 10:     option transport.tcp-user-timeout 0
 11:     option transport.socket.keepalive-time 20
 12:     option transport.socket.keepalive-interval 2
 13:     option transport.socket.keepalive-count 9
 14:     option send-gids true
 15: end-volume
 

So, in the volfile you get in the log file of the snapshot brick process (there should be one snapshot brick process which multiplexes multiple snapshot bricks into one single process) you should not see a reference to a client xlator like above. Instead, you should have a description about a xlator whose type is printed as protocol/server. 

NOTE: protocol/server is not the only xlator that is unique to a brick process. There are several other xlators that are present in a brick process, but not in a client process.

Please let me know if this is sufficient. If you need confirmation from my side as to whether the multiplexed snapshot brick process remained a brick after the restore of one of the snapshots and did not become client (it should not), you can do one of the following things.

1) Share the log file of the multiplexed snapshot brick process after your tests are done. (i.e. attach here, from all nodes)

2) Share /var/log/glusterfs directory itself here (from all nodes)

If you are going to attach logs here (either log file of multiplexed snapshot brick process or /var/log/glusterfs), please clear /var/log/glusterfs from all the nodes before you run your tests. This ensures that the logs you have uploaded are only from this test and avoids confusion.
Comment 14 Anjana KD 2018-12-04 11:37:34 UTC 
Updated the doc text in doc text field. Kindly review for technical accuracy
Comment 15 errata-xmlrpc 2018-12-17 17:07:11 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:3827
Comment 16 Red Hat Bugzilla 2023-09-14 04:39:30 UTC 
The needinfo request[s] on this closed bug have been removed as they have been unresolved for 1000 days
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