[Gluster-users] Rebalancing newly added bricks
Nithya Balachandran
nbalacha at redhat.com
Thu Sep 12 05:18:08 UTC 2019
On Wed, 11 Sep 2019 at 09:47, Strahil <hunter86_bg at yahoo.com> wrote:
> Hi Nithya,
>
> I just reminded about your previous e-mail which left me with the
> impression that old volumes need that.
> This is the one 1 mean:
>
> >It looks like this is a replicate volume. If >that is the case then yes,
> you are >running an old version of Gluster for >which this was the default
>
Hi Strahil,
I'm providing a little more detail here which I hope will explain things.
Rebalance was always a volume wide operation - a *rebalance start*
operation will start rebalance processes on all nodes of the volume.
However, different processes would behave differently. In earlier releases,
all nodes would crawl the bricks and update the directory layouts. However,
only one node in each replica/disperse set would actually migrate files,so
the rebalance status would only show one node doing any "work" (scanning,
rebalancing etc). However, this one node will process all the files in its
replica sets. Rerunning rebalance on other nodes would make no difference
as it will always be the same node that ends up migrating files.
So for instance, for a replicate volume with server1:/brick1,
server2:/brick2 and server3:/brick3 in that order, only the rebalance
process on server1 would migrate files. In newer releases, all 3 nodes
would migrate files.
The rebalance status does not capture the directory operations of fixing
layouts which is why it looks like the other nodes are not doing anything.
Hope this helps.
Regards,
Nithya
> behaviour.
>
> >
> >
>
> >Regards,
>
> >
>
> >Nithya
>
>
> Best Regards,
> Strahil Nikolov
> On Sep 9, 2019 06:36, Nithya Balachandran <nbalacha at redhat.com> wrote:
>
>
>
> On Sat, 7 Sep 2019 at 00:03, Strahil Nikolov <hunter86_bg at yahoo.com>
> wrote:
>
> As it was mentioned, you might have to run rebalance on the other node -
> but it is better to wait this node is over.
>
>
> Hi Strahil,
>
> Rebalance does not need to be run on the other node - the operation is a
> volume wide one . Only a single node per replica set would migrate files in
> the version used in this case .
>
> Regards,
> Nithya
>
> Best Regards,
> Strahil Nikolov
>
> В петък, 6 септември 2019 г., 15:29:20 ч. Гринуич+3, Herb Burnswell <
> herbert.burnswell at gmail.com> написа:
>
>
>
>
> On Thu, Sep 5, 2019 at 9:56 PM Nithya Balachandran <nbalacha at redhat.com>
> wrote:
>
>
>
> On Thu, 5 Sep 2019 at 02:41, Herb Burnswell <herbert.burnswell at gmail.com>
> wrote:
>
> Thanks for the replies. The rebalance is running and the brick
> percentages are not adjusting as expected:
>
> # df -hP |grep data
> /dev/mapper/gluster_vg-gluster_lv1_data 60T 49T 11T 83%
> /gluster_bricks/data1
> /dev/mapper/gluster_vg-gluster_lv2_data 60T 49T 11T 83%
> /gluster_bricks/data2
> /dev/mapper/gluster_vg-gluster_lv3_data 60T 4.6T 55T 8%
> /gluster_bricks/data3
> /dev/mapper/gluster_vg-gluster_lv4_data 60T 4.6T 55T 8%
> /gluster_bricks/data4
> /dev/mapper/gluster_vg-gluster_lv5_data 60T 4.6T 55T 8%
> /gluster_bricks/data5
> /dev/mapper/gluster_vg-gluster_lv6_data 60T 4.6T 55T 8%
> /gluster_bricks/data6
>
> At the current pace it looks like this will continue to run for another
> 5-6 days.
>
> I appreciate the guidance..
>
>
> What is the output of the rebalance status command?
> Can you check if there are any errors in the rebalance logs on the node
> on which you see rebalance activity?
> If there are a lot of small files on the volume, the rebalance is expected
> to take time.
>
> Regards,
> Nithya
>
>
> My apologies, that was a typo. I meant to say:
>
> "The rebalance is running and the brick percentages are NOW adjusting as
> expected"
>
> I did expect the rebalance to take several days. The rebalance log is not
> showing any errors. Status output:
>
> # gluster vol rebalance tank status
> Node Rebalanced-files size
> scanned failures skipped status run time in
> h:m:s
> --------- ----------- -----------
> ----------- ----------- ----------- ------------
> --------------
> localhost 1251320 35.5TB
> 2079527 0 0 in progress 139:9:46
> serverB 0
> 0Bytes 7 0 0 completed
> 63:47:55
> volume rebalance: tank: success
>
> Thanks again for the guidance.
>
> HB
>
>
>
>
>
> On Mon, Sep 2, 2019 at 9:08 PM Nithya Balachandran <nbalacha at redhat.com>
> wrote:
>
>
>
> On Sat, 31 Aug 2019 at 22:59, Herb Burnswell <herbert.burnswell at gmail.com>
> wrote:
>
> Thank you for the reply.
>
> I started a rebalance with force on serverA as suggested. Now I see
> 'activity' on that node:
>
> # gluster vol rebalance tank status
> Node Rebalanced-files size
> scanned failures skipped status run time in
> h:m:s
> --------- ----------- -----------
> ----------- ----------- ----------- ------------
> --------------
> localhost 6143 6.1GB
> 9542 0 0 in progress 0:4:5
> serverB 0 0Bytes
> 7 0 0 in progress 0:4:5
> volume rebalance: tank: success
>
> But I am not seeing any activity on serverB. Is this expected? Does the
> rebalance need to run on each node even though it says both nodes are 'in
> progress'?
>
>
> It looks like this is a replicate volume. If that is the case then yes,
> you are running an old version of Gluster for which this was the default
> behaviour.
>
> Regards,
> Nithya
>
> Thanks,
>
> HB
>
> On Sat, Aug 31, 2019 at 4:18 AM Strahil <hunter86_bg at yahoo.com> wrote:
>
> The rebalance status show 0 Bytes.
>
> Maybe you should try with the 'gluster volume rebalance <VOLNAME> start
> force' ?
>
> Best Regards,
> Strahil Nikolov
>
> Source:
> <https://docs.gluster.org/en/latest/Administrator%20Guide/Managing%20Volumes/#rebalancing-volumes>
> https://docs.gluster.org/en/latest/Administrator%20Guide/Managing%20Volumes/#rebalancing-volumes
> On Aug 30, 2019 20:04, Herb Burnswell <herbert.burnswell at gmail.com> wrote:
>
> All,
>
> RHEL 7.5
> Gluster 3.8.15
> 2 Nodes: serverA & serverB
>
> I am not deeply knowledgeable about Gluster and it's administration but we
> have a 2 node cluster that's been running for about a year and a half. All
> has worked fine to date. Our main volume has consisted of two 60TB bricks
> on each of the cluster nodes. As we reached capacity on the volume we
> needed to expand. So, we've added four new 60TB bricks to each of the
> cluster nodes. The bricks are now seen, and the total size of the volume
> is as expected:
>
> # gluster vol status tank
> Status of volume: tank
> Gluster process TCP Port RDMA Port Online
> Pid
>
> ------------------------------------------------------------------------------
> Brick serverA:/gluster_bricks/data1 49162 0 Y
> 20318
> Brick serverB:/gluster_bricks/data1 49166 0 Y
> 3432
> Brick serverA:/gluster_bricks/data2 49163 0 Y
> 20323
> Brick serverB:/gluster_bricks/data2 49167 0 Y
> 3435
> Brick serverA:/gluster_bricks/data3 49164 0 Y
> 4625
> Brick serverA:/gluster_bricks/data4 49165 0 Y
> 4644
> Brick serverA:/gluster_bricks/data5 49166 0 Y
> 5088
> Brick serverA:/gluster_bricks/data6 49167 0 Y
> 5128
> Brick serverB:/gluster_bricks/data3 49168 0 Y
> 22314
> Brick serverB:/gluster_bricks/data4 49169 0 Y
> 22345
> Brick serverB:/gluster_bricks/data5 49170 0 Y
> 22889
> Brick serverB:/gluster_bricks/data6 49171 0 Y
> 22932
> Self-heal Daemon on localhost N/A N/A Y
> 22981
> Self-heal Daemon on <http://serverA.example.com>serverA.example.com N/A
> N/A Y 6202
>
> After adding the bricks we ran a rebalance from serverA as:
>
> # gluster volume rebalance tank start
>
> The rebalance completed:
>
> # gluster volume rebalance tank status
> Node Rebalanced-files size
> scanned failures skipped status run time in
> h:m:s
> --------- ----------- -----------
> ----------- ----------- ----------- ------------
> --------------
> localhost 0 0Bytes
> 0 0 0 completed 3:7:10
> <http://serverA.example.com>
> serverA.example.com 0 0Bytes 0 0
> 0 completed 0:0:0
> volume rebalance: tank: success
>
> However, when I run a df, the two original bricks still show all of the
> consumed space (this is the same on both nodes):
>
> # df -hP
> Filesystem Size Used Avail Use% Mounted on
> /dev/mapper/vg0-root 5.0G 625M 4.4G 13% /
> devtmpfs 32G 0 32G 0% /dev
> tmpfs 32G 0 32G 0% /dev/shm
> tmpfs 32G 67M 32G 1% /run
> tmpfs 32G 0 32G 0%
> /sys/fs/cgroup
> /dev/mapper/vg0-usr 20G 3.6G 17G 18% /usr
> /dev/md126 1014M 228M 787M 23% /boot
> /dev/mapper/vg0-home 5.0G 37M 5.0G 1% /home
> /dev/mapper/vg0-opt 5.0G 37M 5.0G 1% /opt
> /dev/mapper/vg0-tmp 5.0G 33M 5.0G 1% /tmp
> /dev/mapper/vg0-var 20G 2.6G 18G 13% /var
> /dev/mapper/gluster_vg-gluster_lv1_data 60T 59T 1.1T 99%
> /gluster_bricks/data1
> /dev/mapper/gluster_vg-gluster_lv2_data 60T 58T 1.3T 98%
> /gluster_bricks/data2
> /dev/mapper/gluster_vg-gluster_lv3_data 60T 451M 60T 1%
> /gluster_bricks/data3
> /dev/mapper/gluster_vg-gluster_lv4_data 60T 451M 60T 1%
> /gluster_bricks/data4
> /dev/mapper/gluster_vg-gluster_lv5_data 60T 451M 60T 1%
> /gluster_bricks/data5
> /dev/mapper/gluster_vg-gluster_lv6_data 60T 451M 60T 1%
> /gluster_bricks/data6
> localhost:/tank 355T 116T 239T 33% /mnt/tank
>
> We were thinking that the used space would be distributed across the now 6
> bricks after rebalance. Is that not what a rebalance does? Is this
> expected behavior?
>
> Can anyone provide some guidance as to what the behavior here and if there
> is anything that we need to do at this point?
>
> Thanks in advance,
>
> HB
>
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