[Lustre-discuss] Confusion about failover

[Dhruv]

This is a duplicate post by mistake.Kindly ignore
Please refer the discussion "Confusion with failover".

On Jun 26, 11:02 am, Dhruv <DhruvDes... at gmail.com> wrote:
> Hello Everybody,
> I am a novice in using Lustre. Wanted some help.
>
> Case1:
> I tried the ost failover . Following is the config file to generate
> xml file.
>
> rm -f failover_2node.xml
> ./lmc -m failover_2node.xml --add net --node node-mds --nid sm01 --
> nettype tcp
> ./lmc -m failover_2node.xml --add net --node node-ost1 --nid sm02 --
> nettype tcp
> ./lmc -m failover_2node.xml --add net --node node-ost2 --nid sm06 --
> nettype tcp
> ./lmc -m failover_2node.xml --add net --node client --nid '*' --
> nettype tcp
>
> # Cofigure MDS
> ./lmc -m failover_2node.xml --add mds --node node-mds --mds mds_test --
> fstype ldiskfs --dev /dev/sdb5
>
> # Cofigure LOV
> ./lmc -m failover_2node.xml --add lov --lov lov_test --mds mds_test --
> stripe_sz 1048576 --stripe_cnt 2 --stripe_pattern 0
>
> # Configures OSTs
> ./lmc -m failover_2node.xml --add ost --node node-ost1 --lov lov_test
> --ost ost1 --failover --fstype ldiskfs --dev /dev/sdb1
> ./lmc -m failover_2node.xml --add ost --node node-ost2 --lov lov_test
> --ost ost1 --failover --fstype ldiskfs --dev /dev/sdb7
>
> # Configure client (this is a 'generic' client used for all client
> mounts)
> ./lmc -m failover_2node.xml --add mtpt --node client --path /mnt/
> lustre --mds mds_test --lov lov_test
>
> .
> Following were my lconf commands.
>
> 1. lconf --reformat --node node-ost1 failover_2node.xml   .... on sm02
> 2. lconf --reformat --node node-ost2 --service=ost1
> failover_2node.xml .... on sm06
> 3. lconf --reformat --node node-mds failover_2node.xml.... on sm01
> 4. lconf --node client failover_2node.xml ... on sm02 and sm06
>
> So my intention is to keep a failover ost node incase one fails. MDS
> is on a seperate node. I tried different scenarios where one ost goes
> down and still data can be retrieved from other. New files can be
> created and old can be deleted on the failover ost. Data was available
> most of time.
>
> So my question is whether Linux HA required to configure such failover
> scenario?
>
> Case2:
> I tried with same sort of formula as shown above for a failover MDS.
> But when the main MDS fails, it doesnt switches to new MDS. Also when
> the main MDS comes up again, the file system doesnt recover. I brought
> down the client and again brought up. Then it was working.
>
> So is Linux HA or similar program necessary for configuring failover??
>
> Dhruv
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