HPE bug-id: LUS-10648
Reproduced with lustre 2.15:
snapshot config used:
[root@cslmo1602 ~]# cat /etc/ldev.conf #local foreign/- label [md|zfs:]device-path [journal-path]/- [raidtab] cslmo1602 cslmo1603 testfs-MDT0000 zfs:pool-mds65/mdt65 cslmo1603 cslmo1602 testfs-MDT0001 zfs:pool-mds66/mdt66 cslmo1604 cslmo1605 testfs-OST0000 zfs:pool-oss0/ost0 cslmo1605 cslmo1604 testfs-OST0001 zfs:pool-oss1/ost1 cslmo1606 cslmo1607 testfs-OST0002 zfs:pool-oss0/ost0 cslmo1607 cslmo1606 testfs-OST0003 zfs:pool-oss1/ost1
Lustre targets when nodes are in a failed-over state:
[root@cslmo1600 ~]# pdsh -g lustre mount -t lustre | sort cslmo1602: pool-mds65/mdt65 on /data/mdt65 type lustre (ro,svname=testfs-MDT0000,mgs,osd=osd-zfs) cslmo1602: pool-mds66/mdt66 on /data/mdt66 type lustre (ro,svname=testfs-MDT0001,mgsnode=:10.230.26.5@o2ib,10.230.26.6@o2ib:10.230.26.7@o2ib,10.230.26.8@o2ib,osd=osd-zfs) cslmo1605: pool-oss0/ost0 on /data/ost0 type lustre (ro,svname=testfs-OST0000,mgsnode=:10.230.26.5@o2ib,10.230.26.6@o2ib:10.230.26.7@o2ib,10.230.26.8@o2ib,osd=osd-zfs) cslmo1605: pool-oss1/ost1 on /data/ost1 type lustre (ro,svname=testfs-OST0001,mgsnode=:10.230.26.5@o2ib,10.230.26.6@o2ib:10.230.26.7@o2ib,10.230.26.8@o2ib,osd=osd-zfs) cslmo1606: pool-oss0/ost0 on /data/ost0 type lustre (ro,svname=testfs-OST0002,mgsnode=:10.230.26.5@o2ib,10.230.26.6@o2ib:10.230.26.7@o2ib,10.230.26.8@o2ib,osd=osd-zfs) cslmo1606: pool-oss1/ost1 on /data/ost1 type lustre (ro,svname=testfs-OST0003,mgsnode=:10.230.26.5@o2ib,10.230.26.6@o2ib:10.230.26.7@o2ib,10.230.26.8@o2ib,osd=osd-zfs)
Before PATCH:
=========
snapshot create:
[root@cslmo1602 ~]# lctl snapshot_create -F testfs -n snap1 ssh: connect to host cslmo1604 port 22: No route to host Can't create the snapshot snap1 [root@cslmo1602 ~]# lctl snapshot_list -F testfs filesystem_name: testfs snapshot_name: pre_snap create_time: Thu Jul 7 16:19:49 2022 modify_time: Thu Jul 7 16:19:49 2022 snapshot_fsname: 01a29921 status: not mount [root@cslmo1602 ~]#
snapshot list:
[root@cslmo1602 ~]# lctl snapshot_list -F testfs -d filesystem_name: testfs snapshot_name: pre_snap snapshot_role: MDT0000 create_time: Thu Jul 7 16:19:49 2022 modify_time: Thu Jul 7 16:19:49 2022 snapshot_fsname: 01a29921 status: not mount snapshot_role: MDT0001 cannot open 'pool-mds66/mdt66@pre_snap': dataset does not exist status: not mount snapshot_role: OST0000 cannot open 'pool-oss0/ost0@pre_snap': dataset does not exist status: not mount snapshot_role: OST0001 create_time: Thu Jul 7 16:19:49 2022 modify_time: Thu Jul 7 16:19:49 2022 snapshot_fsname: 01a29921 status: not mount snapshot_role: OST0002 snapshot_fsname: 01a29921 modify_time: Thu Jul 7 16:19:49 2022 create_time: Thu Jul 7 16:19:49 2022 status: not mount snapshot_role: OST0003 cannot open 'pool-oss1/ost1@pre_snap': dataset does not exist status: not mount
snapshot mount/umount:
[root@cslmo1602 ~]# lctl snapshot_mount -F testfs -n pre_snap mount.lustre: pool-mds66/mdt66@pre_snap has not been formatted with mkfs.lustre or the backend filesystem type is not supported by this tool mount.lustre: pool-oss0/ost0@pre_snap has not been formatted with mkfs.lustre or the backend filesystem type is not supported by this tool mount.lustre: pool-oss1/ost1@pre_snap has not been formatted with mkfs.lustre or the backend filesystem type is not supported by this tool 3 of 6 pieces of the snapshot pre_snap can't be mounted: No such device
snapshot modify:
[root@cslmo1602 ~]# lctl snapshot_modify -F testfs -n pre_snap -N mod_snap cannot open 'pool-oss0/ost0@pre_snap': dataset does not exist cannot open 'pool-mds66/mdt66@pre_snap': dataset does not exist cannot open 'pool-oss1/ost1@pre_snap': dataset does not exist Can't modify the snapshot pre_snap
snapshot destroy:
[root@cslmo1602 ~]# lctl snapshot_destroy -F testfs -n pre_snap Miss snapshot piece on the OST0000. Use '-f' option if want to destroy it by force. Can't destroy the snapshot pre_snap [root@cslmo1602 ~]#
After PATCH:
========
Applied lustre fix:
snapshot create:
[root@cslmo1602 ~]# lctl snapshot_create -F testfs -n snap1 [root@cslmo1602 ~]#
snapshot list:
[root@cslmo1602 ~]# lctl snapshot_list -F testfs filesystem_name: testfs snapshot_name: snap1 modify_time: Fri Jul 8 14:06:05 2022 create_time: Fri Jul 8 14:06:05 2022 snapshot_fsname: 4d4aaffb status: not mount filesystem_name: testfs snapshot_name: pre_snap create_time: Thu Jul 7 16:19:49 2022 modify_time: Thu Jul 7 16:35:34 2022 snapshot_fsname: 01a29921 status: not mount [root@cslmo1602 ~]# [root@cslmo1602 ~]# lctl snapshot_list -F testfs -n snap1 -d filesystem_name: testfs snapshot_name: snap1 snapshot_role: MDT0000 modify_time: Fri Jul 8 14:06:05 2022 create_time: Fri Jul 8 14:06:05 2022 snapshot_fsname: 4d4aaffb status: not mount snapshot_role: MDT0001 modify_time: Fri Jul 8 14:06:05 2022 create_time: Fri Jul 8 14:06:05 2022 snapshot_fsname: 4d4aaffb status: not mount snapshot_role: OST0000 create_time: Fri Jul 8 14:06:05 2022 modify_time: Fri Jul 8 14:06:05 2022 snapshot_fsname: 4d4aaffb status: not mount snapshot_role: OST0001 snapshot_fsname: 4d4aaffb create_time: Fri Jul 8 14:06:05 2022 modify_time: Fri Jul 8 14:06:05 2022 status: not mount snapshot_role: OST0002 snapshot_fsname: 4d4aaffb create_time: Fri Jul 8 14:06:05 2022 modify_time: Fri Jul 8 14:06:05 2022 status: not mount snapshot_role: OST0003 create_time: Fri Jul 8 14:06:05 2022 modify_time: Fri Jul 8 14:06:05 2022 snapshot_fsname: 4d4aaffb status: not mount [root@cslmo1602 ~]#
snapshot mount/umount:
[root@cslmo1602 ~]# lctl snapshot_mount -F testfs -n snap1 mounted the snapshot snap1 with fsname 4d4aaffb [root@cslmo1602 ~]# [root@cslmo1602 ~]# lctl snapshot_umount -F testfs -n snap1 [root@cslmo1602 ~]#
snapshot modify:
[root@cslmo1602 ~]# lctl snapshot_modify -F testfs -n snap1 -N Snap1 [root@cslmo1602 ~]#
snapshot destroy:
[root@cslmo1602 ~]# lctl snapshot_destroy -F testfs -n Snap1 [root@cslmo1602 ~]# [root@cslmo1602 ~]# lctl snapshot_list -F testfs -n Snap1 Can't list the snapshot Snap1 [root@cslmo1602 ~]#
With the fix applied, we will be able to create/destroy/modify/list/mount/umount a lustre snapshot even when lustre targets are failed over to the partner nodes as defined by the /etc/ldev.conf configuration file. Previously this would fail as foreign host field in /etc/ldev.conf configuration file was ignored.
pjones, can you please assign this to akash-b? Jira gives me some "communications breakdown" error when I try to do it.
Cory
I think that was JIRA's helpful error message to tell you that Akash B was not a valid selection 
I have added Akash B into the developers group and now tickets can be assigned ok
Peter
CR/Patch: https://review.whamcloud.com/#/c/48226/
Subject: LU-16072 utils: snapshot support to foreign host
Project: fs/lustre-release
Branch: master
"Oleg Drokin <green@whamcloud.com>" merged in patch https://review.whamcloud.com/c/fs/lustre-release/+/48226/
Subject: LU-16072 utils: snapshot support to foreign host
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 815ca64afc8e54f9707ed9f458e14a9c99629ed7
Landed for 2.16