[LU-12530] udev add/change rule loads zfs module on clients

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.14.0, Lustre 2.12.4
• Affects Version/s: Lustre 2.10.5, Lustre 2.12.2
• Severity: 3
• Assignee: Nathaniel Clark
• Reporter: Olaf Faaland

Description

Lustre loads the zfs module whenever a block device is added or changed, if Lustre was built against zfs. It unintentionally does this on clients as well as servers.

Commit 0d11a314787bc795797a016262e9bcfe86e2193e for LU-11563 added a udev rule,
lustre/conf/99-lustre-server.rules

When a block device is added or changed:
udev -> l_tunedisk
l_tunedisk -> mount_utils.c:osd_init()
osd_init() > backfs_ops[]>init() AKA zfs_init()
zfs_init() -> "/sbin/modprobe -q zfs"

This occurs if the Lustre rpms installed are a full build of Lustre, instead of just a client build.

Issue Links

• is related to: LU-10599 Possible for ID_FS_TYPE to be lustre / ldiskfs?
• is related to: LU-9551 I/O errors when lustre uses multipath devices
• is related to: LU-11736 Do not apply bulk IO tuning on MDT or MGT devices