Two centos 7 servers with SAN storage over FC

[aboamir]

Dears,

Would you please advise if below configuration is a possible one:

Two centos 7 servers connected to San storage over FC, and will have pacemaker cluster between the two centos 7 servers ( node1 and node2)


If not possible, please advise about the limitation and how to work around

Your fast response is highly appreciated


Thank you

[BShT]

https://www.unixarena.com/2016/01/rhel7 ... ster.html/

ps: a fast response usually comes from a proper support contract

[TrevorH]

That depends on what you want to do with it.

If you want both systems to access the same filesystem simultaneously then you should review your requirements and try to avoid needing such a situation.

If you absolutely require simultaneous access from both systems at the same time then you will need to look at using a cluster aware filesystem such as GFS2. You cannot and must not attempt to use an ordinary filesystem like xfs or ext[234] at the same time from more than one system. Doing so will lead to immediate and catastrophic filesystem corruption with probable loss of all data. Using GFS2 is slow and will require you to set up and configure and test fencing (a.k.a STONITH) and will also require use of the DLM. Access will be (relatively) slow and prone to lockups even with all the above in place.

You can use xfs/ext[234] only if you mount the filesystem on one machine at a time and set up pacemaker to switch between them. It is extremely important that both systems never attempt to mount the filesystem at the same time. This is why fencing is required even if you do not use GFS2.

Oh, and don't forget the fencing.

And don't forget to test every single failure scenario that you can think of in advance before you go into production. And test it multiple times to be sure.

And finally, CentOS 7 has less than 18 months life left. You should probably not deploy it to new systems as you will need to migrate to something else in 18 months time. There is no CentOS 8 or 9 (only the beta "Stream" versions) so you should look at using Alma, Rocky or Oracle Enterprise Linux (all are rebuilds of RHEL) or even RHEL. CentOS Stream is not suitable for production use.