Re: proper way to temporarily remove brick server from replica cluster to avoid kvm guest disruption

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



[root@vh1 ~]# gluster volume info vol1

Volume Name: vol1
Type: Replicate
Volume ID: dfd681bb-5b68-4831-9863-e13f9f027620
Status: Started
Snapshot Count: 0
Number of Bricks: 1 x 4 = 4
Transport-type: tcp
Bricks:
Brick1: vh1:/pool/gluster/brick1/data
Brick2: vh2:/pool/gluster/brick1/data
Brick3: vh3:/pool/gluster/brick1/data
Brick4: vh4:/pool/gluster/brick1/data
Options Reconfigured:
transport.address-family: inet
nfs.disable: on
performance.client-io-threads: off


[root@vh1 ~]# gluster pool list
UUID                                    Hostname        State
75fc4258-fabd-47c9-8198-bbe6e6a906fb    vh2             Connected
00697e28-96c0-4534-a314-e878070b653d    vh3             Connected
2a9b891b-35d0-496c-bb06-f5dab4feb6bf    vh4             Connected
8ba6fb80-3b13-4379-94cf-22662cbb48a2    vh5             Disconnected
1298d334-3500-4b40-a8bd-cc781f7349d0    vh6             Connected
79a533ac-3d89-44b9-b0ce-823cfec8cf75    vh7             Connected
4141cd74-9c13-404c-a02c-f553fa19bc22    vh8             Connected


On Sat, 5 Mar 2022, Strahil Nikolov wrote:

Hey Todd,

can you provide 'gluster volume info <VOLUME>' ?

Best Regards,
Strahil Nikolov

      On Sat, Mar 5, 2022 at 18:17, Todd Pfaff
<pfaff@xxxxxxxxxxxxxxxxx> wrote:
I have a replica volume created as:

gluster volume create vol1 replica 4 \
  host{1,2,3,4}:/mnt/gluster/brick1/data \
  force


All hosts host{1,2,3,4} mount this volume as:

localhost:/vol1 /mnt/gluster/vol1 glusterfs defaults


Some other hosts are trusted peers but do not contribute bricks, and
they
also mount vol1 in the same way:

localhost:/vol1 /mnt/gluster/vol1 glusterfs defaults


All hosts run CentOS 7.9, and all are running glusterfs 9.4 or 9.5 from
centos-release-gluster9-1.0-1.el7.noarch.


All hosts run kvm guests that use qcow2 files for root filesystems that
are stored on gluster volume vol1.


This is all working well, as long as none of host{1,2,3,4} go offline.


I want to take one of host{1,2,3,4} offline temporarily for
maintenance.
I'll refer to this as hostX.

I understand that hostX will need to be healed when it comes back
online.

I would, of course, migrate guests from hostX to another host, in which
case hostX would then only be participating as a gluster replica brick
provider and serving gluster client requests.

What I've experienced is that if I take one of host{1,2,3,4} offline,
this
can disrupt some of the VM guests on various other hosts such that
their
root filesystems go to read-only.

What I'm looking for here are suggestions as to how to properly take
one
of host{1,2,3,4} offline to avoid such disruption or how to tune the
libvirt kvm hosts and guests to be sufficiently resilient in the face
of
taking one gluster replica node offline.

Thanks,
Todd
________



Community Meeting Calendar:

Schedule -
Every 2nd and 4th Tuesday at 14:30 IST / 09:00 UTC
Bridge: https://meet.google.com/cpu-eiue-hvk
Gluster-users mailing list
Gluster-users@xxxxxxxxxxx
https://lists.gluster.org/mailman/listinfo/gluster-users



________



Community Meeting Calendar:

Schedule -
Every 2nd and 4th Tuesday at 14:30 IST / 09:00 UTC
Bridge: https://meet.google.com/cpu-eiue-hvk
Gluster-users mailing list
Gluster-users@xxxxxxxxxxx
https://lists.gluster.org/mailman/listinfo/gluster-users




[Index of Archives]     [Gluster Development]     [Linux Filesytems Development]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux