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OS Upgrade on RAC Database Servers

Smit Patel
Smit Patel Member Posts: 34

Hi Experts,

We are planning to upgrade OS on production databases from RHEL 6.5 to RHEL 6.8.

Currently we are evaluating approach for upgrade and we found below two oracle support notes with two different approaches:

1) How To Upgrade ASMLib Kernel Driver as Part of Kernel Upgrade? (Doc ID 1391807.1)   (Non Rolling Upgrade)

2) How to Manage Oracle Grid Infrastructure During Operating System Upgrades (Doc ID 1559762.1)  (Rolling upgrade)

We are using asmlib for configuration of ASM disks. Below version of oracle asm RPMs are installed on database servers.

kmod-oracleasm-2.0.6.rh1-2.el6.x86_64

oracleasm-support-2.1.8-1.el6.x86_64
oracleasmlib-2.0.4-1.el6.x86_64

We need assistance for below queries :

1. Do we need to upgrade above oracleasm RPMs during or post OS upgrade ? If yes what should be target version.

2. If we choose rolling upgrade, is there any risk in case of different OS version in same RAC (i.e RHEL 6.5 on some nodes and 6.8 on upgraded nodes)?

Thanks and Regards,

Smit

Tagged:
Smit Patel

Answers

  • abhilash8
    abhilash8 Member Posts: 6 Blue Ribbon
    edited August 2019

    I think this needs to be tested and retested , the documentation (Doc ID 1559762.1) is right in relinking of needed

    It is possible that the ASM can scan all disks without upgrading the ASM Drivers after an upgrade.

    Are you using multipath settiings ?

    Configuring Oracle ASMLib on Multipath Disks on Linux (Doc ID 394956.1)

    It is advisable to to take a ASM Metadata backup using md_backup

    https://docs.oracle.com/database/121/OSTMG/GUID-D23C36FA-D1C8-4F82-A82A-5F3EA6E01623.htm#OSTMG94578 

    Smit Patel
  • Cobert
    Cobert Member Posts: 564 Silver Badge
    edited September 2019

    Hi,

    You do not outline your upgrade strategy.

    Do you have dataguard / DR?

    How many nodes in the cluster?

    Re. ASMLIB, is there any reason not to go for OEL? It bakes in asmlib.

    Per the ASM support on MOS, ASLLIB always needs a matching kernel driver.

    https://www.oracle.com/technetwork/server-storage/linux/update-driver-095781.html

    You need to use the oracleasm update-driver utility after upgrading the OS.

    I've previously run extended RAC with OEL 5.x to OEL 7, same version of Oracle, moving instances from physical nodes to VMs with updated kernels. It's possible, but not recommended for protracted periods of time. As always, you need to run tests in non production and try to simulate workload using Jmeter, Loadrunner etc. We had a lot of node evictions due to kernel differences, so the easier way to upgrade would be to build your DR node or nodes, flip the DB over to that, possibly even as your DR, then have


    Is there a reason that you are not upgrading to RHEL 7?

    RHEL 8 has just been announced, by upgrading to 6.8 you are potentially forward loading future upgrades / dependencies.

    Good luck!

    Smit Patel
  • Cobert
    Cobert Member Posts: 564 Silver Badge
    edited September 2019

    A fair point on OL / OEL, force of habit

    @Smit Patel, in our customers case we added nodes, as such could remove them in the event of issue / move instances back to the original node, but this was a major version change. As @Dude! cites, not upgrading, but gradually moving to the newer nodes. We found this to be a better option as didn't entirely destroy limited infrastructure, kept SCAN simple and no dependency on moving to DR, but is entirely dependent on your site setup.

    Smit Patel
  • Smit Patel
    Smit Patel Member Posts: 34
    edited December 2019

    Thanks @Cobert & @Dude! for your responses on this thread and apologies for late reply.

    We have confirmed from Oracle Support and below action plan have been suggested by them.

    1. Upgrade OS in nodes  and relink binaries in rolling method

    2. We should not run different OS version/kernel version for RAC, but for shorter time(suggested 24 hours) it will work.

    We have completed one round of testing with non prod environment. I will further update you on this after final testing on non prod setup.

    BR,

    Smit Patel

  • eronitascott
    eronitascott Member Posts: 9 Green Ribbon
    edited January 2020

    There is no upgrade path for RHEL 6 to 7, not with any products installed, such as Oracle. It will have to be a complete setup from scratch and may involve a database patch or upgrade.

    Real Application Cluster (RAC) is a component of the Oracle 9i database product that allows a database to be installed across multiple servers.

  • user13448254
    user13448254 Member Posts: 2

    I get that RAC allows databases to be installed across multiple servers. Does RAC work on VMware based clusters? Also what if we are migrating from an older version say 10G to a later one like 19C version? Does anyone know of any issues with 19C not being supported by VMWare ESX clusters?

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