[lustre-discuss] Migrating an older MGS to a new server with new storage and new IP

Nehring, Shane R [ITS] snehring at iastate.edu
Thu Oct 23 09:15:45 PDT 2025


I've actually been working on fleshing out the process for this on the
wiki https://wiki.lustre.org/ZFS_Snapshots_for_MDT_backup
while the article is more about MDTs it should work for any zfs backed
target.

You should be able to take a snapshot and send the dataset using zfs
send followed by the writeconf for the ip address change, but you need
to make sure you use the -p argument with send so that the dataset
properties (the most important being the lustre:version, lustre:svname,
lustre:index, and lustre:flags properties). This should also hold true
for the mdts.

If you run into issues I'd fall back to the method defined in the
manual.

Shane


On Thu, 2025-10-23 at 14:48 +0000, Andreas Dilger via lustre-discuss
wrote:
> This should be covered under "backup restore MDT" in the Lustre
> manual.  Short answer is "tar --xattrs --include 'trusted.*' ...",
> and then run "writeconf" on all targets to regenerate the config with
> the new IP address.
> 
> > On Oct 22, 2025, at 18:33, Sid Young via lustre-discuss
> > <lustre-discuss at lists.lustre.org> wrote:
> > 
> > 
> > 
> > 
> > 
> > G'Day all,
> > I'm researching how to best move an MGS/MGT on ZFS on a Centos 7.9
> > platform (lustre 2.12.6) (old h/w and old storage) to a new server
> > with Oracle linux 8.10 and different storage (lustre 2.15.5).
> > 
> > The MGS box also has two MDS file systems, "mdt-home / fsname =
> > home" and "mdt-lustre / fsname=lustre" also on ZFS. I will then
> > plan to move (after a successful MGS migration), the MDS
> > functionality to two new servers (one for /home and one for
> > /lustre).
> > 
> > The MGS IP 10.140.93.42 needs to change to 93.50 and then the MDS
> > will need a change later.
> > 
> > So far I can't work out the best way to achieve an MGS migration
> > across platforms with an IP change. There are only 12 clients, so
> > remounting filesystems is not an issue.
> > 
> > Does the OSS also need a config change when the MGS changes? 
> > 
> > Some Info
> > 
> > 
> > 
> > [root at hpc-mds-02 ~]# zfs list
> > NAME               USED  AVAIL  REFER  MOUNTPOINT
> > mdthome           81.5G  4.12T    96K  /mdthome
> > mdthome/home      77.6G  4.12T  77.6G  /mdthome/home
> > mdtlustre         40.9G  5.00T    96K  /mdtlustre
> > mdtlustre/lustre  37.1G  5.00T  37.1G  /mdtlustre/lustre
> > mgspool           9.06M   860G    96K  /mgspool
> > mgspool/mgt       8.02M   860G  8.02M  /mgspool/mgt
> > [root at hpc-mds-02 ~]#
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > [root at hpc-mds-02 ~]# lctl dl
> >   0 UP osd-zfs MGS-osd MGS-osd_UUID 4
> >   1 UP mgs MGS MGS 38
> >   2 UP mgc MGC10.140.93.42 at o2ib a4723a3a-dd8a-667f-0128-
> > 71caf5cc56be 4
> >   3 UP osd-zfs home-MDT0000-osd home-MDT0000-osd_UUID 10
> >   4 UP mgc MGC10.140.93.41 at o2ib 68dff2a2-29d9-1468-6ff0-
> > 6d99fa57d383 4
> >   5 UP mds MDS MDS_uuid 2
> >   6 UP lod home-MDT0000-mdtlov home-MDT0000-mdtlov_UUID 3
> >   7 UP mdt home-MDT0000 home-MDT0000_UUID 40
> >   8 UP mdd home-MDD0000 home-MDD0000_UUID 3
> >   9 UP qmt home-QMT0000 home-QMT0000_UUID 3
> >  10 UP osp home-OST0000-osc-MDT0000 home-MDT0000-mdtlov_UUID 4
> >  11 UP osp home-OST0001-osc-MDT0000 home-MDT0000-mdtlov_UUID 4
> >  12 UP osp home-OST0002-osc-MDT0000 home-MDT0000-mdtlov_UUID 4
> >  13 UP osp home-OST0003-osc-MDT0000 home-MDT0000-mdtlov_UUID 4
> >  14 UP lwp home-MDT0000-lwp-MDT0000 home-MDT0000-lwp-MDT0000_UUID 4
> >  15 UP osd-zfs lustre-MDT0000-osd lustre-MDT0000-osd_UUID 12
> >  16 UP lod lustre-MDT0000-mdtlov lustre-MDT0000-mdtlov_UUID 3
> >  17 UP mdt lustre-MDT0000 lustre-MDT0000_UUID 44
> >  18 UP mdd lustre-MDD0000 lustre-MDD0000_UUID 3
> >  19 UP qmt lustre-QMT0000 lustre-QMT0000_UUID 3
> >  20 UP osp lustre-OST0000-osc-MDT0000 lustre-MDT0000-mdtlov_UUID 4
> >  21 UP osp lustre-OST0001-osc-MDT0000 lustre-MDT0000-mdtlov_UUID 4
> >  22 UP osp lustre-OST0002-osc-MDT0000 lustre-MDT0000-mdtlov_UUID 4
> >  23 UP osp lustre-OST0003-osc-MDT0000 lustre-MDT0000-mdtlov_UUID 4
> >  24 UP osp lustre-OST0004-osc-MDT0000 lustre-MDT0000-mdtlov_UUID 4
> >  25 UP osp lustre-OST0005-osc-MDT0000 lustre-MDT0000-mdtlov_UUID 4
> >  26 UP lwp lustre-MDT0000-lwp-MDT0000 lustre-MDT0000-lwp-
> > MDT0000_UUID 4
> > [root at hpc-mds-02 ~]#
> > 
> > 
> > 
> > 
> > [root at hpc-mds-02 ~]# zpool list
> > NAME        SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP 
> > HEALTH  ALTROOT
> > mdthome    4.34T  81.5G  4.26T         -    49%     1%  1.00x 
> > ONLINE  -
> > mdtlustre  5.20T  40.9G  5.16T         -    47%     0%  1.00x 
> > ONLINE  -
> > mgspool     888G  9.12M   888G         -     0%     0%  1.00x 
> > ONLINE  -
> > [root at hpc-mds-02 ~]#
> > 
> > 
> >   pool: mgspool
> >  state: ONLINE
> >   scan: scrub repaired 0B in 0h0m with 0 errors on Mon Jun 17
> > 13:18:44 2024
> > config:
> > 
> >         NAME         STATE     READ WRITE CKSUM
> >         mgspool      ONLINE       0     0     0
> >           mirror-0   ONLINE       0     0     0
> >             d3710M0  ONLINE       0     0     0
> >             d3710M1  ONLINE       0     0     0
> > 
> > errors: No known data errors
> > [root at hpc-mds-02 ~]#
> > 
> > Sid Young
> > Brisbane, Australia
> > 
> > _______________________________________________
> > lustre-discuss mailing list
> > lustre-discuss at lists.lustre.org
> > http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
> 
> 
> 
> 
> 
> 
> 
> Cheers, Andreas
>> Andreas Dilger
> Lustre Principal Architect
> Whamcloud/DDN
> 
> 
> 
> 
> _______________________________________________
> lustre-discuss mailing list
> lustre-discuss at lists.lustre.org
> http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
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