Lustre upgrading from 2.4.1 to 2.4.2

For upgrading it is recommended to unmount clients. but if you cannot like in my case, just leave them.

Before upgrade make sure that server is stopped:

1. umount OST 
2. umount MDT
3. umount MGS

Note that order is important!
in one server I got kernel panic because of MGS was unmounted before OST went down.


Then remove all lustre  modules from servers:
 service lustre stop;service lnet stop;lustre_rmmod;service lnet stop



Download latest e2fs from:
http://downloads.whamcloud.com/public/e2fsprogs/

NOTE: if you google: "lustre e2fsprogs" you will end up tons of wrong/old links.
The actual one is from whamcloud.com!!!

Install e2fsprogs:
yum install e2fsprogs-1.42.7.wc2-7.el6.x86_64.rpm e2fsprogs-libs-1.42.7.wc2-7.el6.x86_64.rpm libcom_err-1.42.7.wc2-7.el6.x86_64.rpm libss-1.42.7.wc2-7.el6.x86_64.rpm

NOTE: once you installed e2fsprogs you cannot  remove them any more.

The last step is installing all rpms from latest-maintenance-release.

Download  recent lustre from:
http://downloads.whamcloud.com/public/lustre/latest-maintenance-release/el6/server/RPMS/x86_64/

NOTE: If you dont use zfs back-end do not install  lustre-osd-zfs*.

reboot the servers and mount:

1. MGS
2. MDT
3. OSTs 

wait until recovery mode is gone. Go to clients  and df -h should work.
On first hour on heavy loaded cluster you will probably get very hi-load on OSTS and mdt. It is expected, due to parallel commits from the clients.