Storage foundation 6.0 Cluster file system in Linux

[NBU_13]

Hi,

I need the help..

Iam new to Veritas Storage foundation in cluster environment,

for our Client, new implementation.

we are planning to configura Veritas storage foundation Cluster file system 6.0 for Linux.

2 Linux server with 3 disk shared.

Planning to install storage foundation for VCS, CVM, CFS on Linux for some of the application to use this server.

My question is, in  Veritas storage foundation Cluster file system, I/O fencing is neccessary to configure, if yes, can you please tell me.

Why, its needed and how to configure with 3 shared disk.

Thank you,

[mikebounds]

Fencing is required with SFCFS - this is because as multiple nodes write to the same disks, if you get split-brain, then corruption of the data is likely to quickly occur, where as with failover diskgroups, you have to import the diskgroup and mount the filesystem on the other node before any corruption could occur and there are mechnisms like pinging pubic IP which can prevent diskgroup importing.

You can use disk based I/O fencing which requires a minimum of 3 small disks (these must be separate from the data disks) or Server based fencing which requires a minimum of 3 Coordination Point servers (CPS) where CPS servers can be shared between many clusters.

See SFCFS installation guide for more details - http://www.symantec.com/business/support/resources/sites/BUSINESS/content/live/DOCUMENTATION/5000/DO...

Mike

[NBU_13]

Hi,

Thanks for information,

I have 2 servers with Linux Operating system as Virtual machines with 3 shared disk

I have only 3 disk, has shared with 2 servers,

Now, I installed storage foundation on both servers,

configured Vertias cluster server between 2 servers.

configured disk group with 3 disk and shared between 2 server.

created volume, mount point, service group and mounted, in this scenario, which fencing is better to configure and how ?

question : ¨disk based I/O fencing which requires a minimum of 3 small disks (these must be separate from the data disks)¨ means, I want 3 more physical disk, apart from my 3 shared disk ?

[mikebounds · Accepted solution]

I would say dIsk base fencing is better for you to configure as this just requires 3 disks as oppose to setting up 3 servers with CPS.  You need 3 more very small LUNs in addition to your your 3 data LUNs - so Linux should see 6 disks (+ O/S disks), sdb, sdc etc.  To set-up fencing you can use "/opt/VRTS/install/installsfcfsha<version> -fencing" - see "To set up disk-based I/O fencing using the installsfcfsha"section in SFCFS install guide.

Mike

[NBU_13]

Hi Mike,

Thanks for information,

Just for clarification...

So, I need to add 3 more small disk with 2 Linux clster server, apart from current 3 data disks, right ?

can you please let me know minimum size of that 3 small disk to add for disk based I/O fencing ? and also

If I configure I/O fencing with other 3 small disk, it wont affect current 3 data disk´s data and configuration ?

Thanks in Advanced,

Note : ¨dIsk base fencing is better for you to configure as this just requires 3 disks as oppose to setting up 3 servers with CPS.¨ - what is mean CPS ?

[mikebounds]

I have never seen a minimum size given in the guides, but usually it is hard to produce small LUNs, so I think the smallest LUN I have used is 100MB.  The default private region size I think is 64MB (maybe 32MB), so 100MB seems a sensible size.

The 3 new small LUNs will NOT affect current data LUNs

CPS = Coordination Point Server

Mike

[NBU_13]

Hi Mike,

Thanks for your information,