[LU-16072] snapshot support to foreign host

• Type: New Feature
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.16.0
• Affects Version/s: Upstream, Lustre 2.15.0
• Labels: ZFS server
• Environment: Lustre filesystem with ZFS as backend filesystem.

Epic/Theme

zfs

Epic

server zfs

• Assignee: Akash B
• Reporter: Akash B

Description

lctl snapshot create does not work if one of the nodes is not reachable:

It seems like the lctl snapshot commands do not work if the resources fail to the partner node even though the partner node details are mentioned in ldev.conf.

Sample ldev.conf is as follows:

cslmo4702       cslmo4703       testfs-MDT0000  zfs:/dev/pool-mds65/mdt65 - -
cslmo4703       cslmo4702       testfs-MDT0001  zfs:/dev/pool-mds66/mdt66 - -
cslmo4704       cslmo4705       testfs-OST0000  zfs:/dev/pool-oss0/ost0 - -
cslmo4705      cslmo4704       testfs-OST0001  zfs:/dev/pool-oss1/ost1 - -

For eg. let's say there are 2 nodes cslmo4704 & cslmo4705. cslmo4705 is the partner of cslmo4704 and vice versa. cslmo4704 has dataset zfs:/dev/pool-oss0/ost0 and cslmo4705 has dataset zfs:/dev/pool-oss1/ost1. I fail/power off host cslmo4705 and hence the dataset /dev/pool-oss1/ost1 correctly fails over to cslmo4704. cslmo4704 has both datasets. In this situation, if I try to create lustre snapshot using “lctl snapshot create” command, the command fails on the dataset /dev/pool-oss1/ost1.

[root@cslmo4702 ~]# lctl snapshot_create -F testfs -n snap_test5				
ssh: connect to host cslmo4705 port 22: No route to host				
ssh: connect to host cslmo4705 port 22: No route to host				
ssh: connect to host cslmo4705 port 22: No route to host				
Can't create the snapshot snap_test5

Issue Links

• is related to: LU-12638 lsnapshot ignores failover host in ldev.conf