topic Re: HPE servieguard multi_node package not in sync mode on both node in Operating System - Linux

HPE servieguard multi_node package not in sync mode on both node

Syedfurquan — Tue, 14 Mar 2017 13:02:31 GMT

Hello,

I have installed HPE serviceguard with a multinode package. the package are running succesfully on both nodes and are mounted.

Now when I create any files on either of the node it's not reflecting on other node, basically it's not syncing I belive.

OS=RHEL7.2

SG Version = 12.00.50

vgcreated in shared mode and mentioned as "vgchange -as" in package configuration file.

filesystem used is xfs

Any help how to fix this

Thanks,

Re: HPE servieguard multi_node package not in sync mode on both node

Bill Hassell — Wed, 15 Mar 2017 02:32:20 GMT

Service Guard doesn't sync data between nodes. Unless you use a clustered filesystem (not xfs), only one node can read/write data to the portable volume. The other node can see the shared data by moving the package (stop and restart). Additional information about how you have configured your storage between the nodes and where you are writing your file would be useful.

Re: HPE servieguard multi_node package not in sync mode on both node

Syedfurquan — Wed, 15 Mar 2017 07:43:52 GMT

Hi Bill,

Thanks for your reply. As you said the other node can see the sahred data by stop & restart.

SO to test this I created few files on each node respectively but the data was not updation on other node. I tried stopping & restarting the package. Once the package restarted I can see both nodes sync in data and both nodes can see same files.

Now my question here as you said xfs is not cluster file system agree but HPE serviceguard doesn't support GFS2 which is RHEL cluster fs and vxfs is not supported by RHEL. So what fs I should create which is supported on multi_node in RHEL7.

I have 2 nodes with RHEL7.2 OS in VMware Virtual machine. Mapped 1 raw partition disk of 50GB to both the nodes. Created 1 packagae of 10GB with failover type and it works normal.

created 2nd package of 20GB from the same disk as multi_node package.

Below is the cmviewcl -v o/p :

[root@skvlinuxhpsgtest2 testpkg2]# cmviewcl -v

CLUSTER STATUS
HPSG_cluster up

NODE STATUS STATE
skvlinuxhpsgtest1 up running

Cluster_Lock_LUN:
DEVICE STATUS
/dev/sdb up

Network_Parameters:
INTERFACE STATUS NAME
PRIMARY up eno33555456
PRIMARY up eno16784128

NODE STATUS STATE
skvlinuxhpsgtest2 up running

Cluster_Lock_LUN:
DEVICE STATUS
/dev/sdb up

Network_Parameters:
INTERFACE STATUS NAME
PRIMARY up eno16784128
PRIMARY up eno33555456

PACKAGE STATUS STATE AUTO_RUN NODE
pkg1 up running enabled skvlinuxhpsgtest2

Policy_Parameters:
POLICY_NAME CONFIGURED_VALUE
Failover configured_node
Failback manual

Node_Switching_Parameters:
NODE_TYPE STATUS SWITCHING NAME
Primary up enabled skvlinuxhpsgtest1
Alternate up enabled skvlinuxhpsgtest2 (current)

Other_Attributes:
ATTRIBUTE_NAME ATTRIBUTE_VALUE
Style modular
Priority no_priority

MULTI_NODE_PACKAGES

PACKAGE STATUS STATE AUTO_RUN SYSTEM
pkg2 up running enabled no

NODE_NAME STATUS STATE SWITCHING
skvlinuxhpsgtest1 up running enabled

NODE_NAME STATUS STATE SWITCHING
skvlinuxhpsgtest2 up running enabled

Other_Attributes:
ATTRIBUTE_NAME ATTRIBUTE_VALUE
Style modular
Priority no_priority

Thanks,

Syed

Re: HPE servieguard multi_node package not in sync mode on both node

Mike_Chisholm — Wed, 15 Mar 2017 16:08:45 GMT

Syed,

I think you have answered your own question here. You cannot do this in a supported manner with Serviceguard for Linux due to the file system types that are supported. There is no cluster filesystem that is supported today with Serviceguard for Linux. If this is something you really need it would be a good use case to bring up through your sales channel to try to get some attention on it.

Re: HPE servieguard multi_node package not in sync mode on both node

Bill Hassell — Wed, 15 Mar 2017 17:22:17 GMT

The mountpoint where you stored the new files is only available on one node. There is NO sync involved. The other node cannot see the mountpoint at all unless you've something to force-mount the package volumes on the other node. The new files are stored on the shared storage but only one node can see that location. Move the package to node2 and now you'll see the new files. Move it back to node1 and you'll see the files.

Re: HPE servieguard multi_node package not in sync mode on both node

Syedfurquan — Thu, 16 Mar 2017 09:49:34 GMT

Thanks Mike for the reply,

The reason I am wondering is when HPE serviceguard says multi_node features availaible so it must be some way configurable also. I think I am just missing the point where it says the file system requuired for multi_node. Even the HPE documents don't say anything about file system specific to multi_node.

Hi Bill,

As per last post I have posted cmviewcl -v o/p You can see there, pkg2 is mounted on both the nodes same time and both nodes can write or create new file in same dir /testpkg2 at sametime but can't see the files created on other node unless package restart.. once the package restart both nodes can see the files created by other node.

Thanks

Re: HPE servieguard multi_node package not in sync mode on both node

Mike_Chisholm — Thu, 16 Mar 2017 16:20:44 GMT

http://h20565.www2.hpe.com/hpsc/doc/public/display?sp4ts.oid=376220&docLocale=en_US&docId=emr_na-c05343938

page 224

section 6.1.4.54 fs_type

Table 11 - the supported filesystem types are ext3 ext4 XFS Btrfs abd VxFS

None of these are cluster filesystem types and the same filesystem types are supported for both regular failover packages and multi-node packages. There are use cases for multi-node type packages that do not require filesystems as part of those packages so you can use them for that, but simply putting a non-clustered filesystem type in a multi-node package and trying to use it this way will not work because Serviceguard does not do anything special to the filesystem. The kernel still handles the IO and metadata upadating etc. If the filesystem is not a type that is explicitly supported for simultaneous read-write access across multiple servers then there is nothing Serviceguard will do to enable this. You will end up with filesystem corruption just as surely as you would if you manually mounted one of these filesystems on multiple nodes from the command line and proceeded to start doing simultaneous read-write activity from multiple nodes.

Re: HPE servieguard multi_node package not in sync mode on both node

Syedfurquan — Mon, 20 Mar 2017 08:54:01 GMT

Thnak you Mike for your feedback... Agree with you we can use multi_node package in rhel only in the scenario where fs is not used and we are using RAW disk.

Thanks,