Currently I have a single DC cluster with 3 nodes running 4.1.7 version of Scylla. This setup has been running for a long time and I don't want to make changes to this DC, if possible. Now I have a requirement to add another DC cluster with 3 nodes. Can I set up this new DC with the latest stable version of Scylla? Will the two DCs be able to communicate with each other without any issues? Or am I forced to upgrade the existing DC to the latest version?
Scylla supports rolling upgrades, which means you can indeed upgrade just some of the nodes in the cluster while the rest are still running the older version. The cluster should be able to fully work in this state - including the communication between old and new nodes. Not all upgrade paths are equally supported or have been equally tested, obviously, but most "interesting" upgrade paths (a newer release in the same major version, the next major version) are indeed supported.
That being said, while staying at a half-upgraded state for a long time is possible, it is not recommended. It also means that whatever new features or improved algorithms were introduced in the new version, the new nodes will need to avoid them until the full cluster is upgraded.
OSS 4.1.7 is a pretty old OSS release from Oct 2020. The assumption that you can add another DC running OSS 5.0 (latest OSS release from 10 days ago) to the existing cluster, is a bit of a risky one.
The supported upgrade path (QA tested) is from OSS 4.6 to 5.0. You can read more about the upgrade path here: https://docs.scylladb.com/upgrade/upgrade-opensource/
The tested upgrade route is via minor versions 4.1 --> 4.2 --> 4.3 --> 4.4 --> 4.5 --> 4.6 --> 5.0, jumping multiple minor version should work, but we can't say that it was tested.
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I want to keep the my Apache HTTP server to its latest version. So I check https://httpd.apache.org/ and it says 2.4.48 is the latest version. I also check https://en.wikipedia.org/wiki/Apache_HTTP_Server#Versions and it says the latest version is 2.4.48 (June 1, 2021; 2 months ago[2])
However, I also see this https://httpd.apache.org/docs/trunk/ and it seems there is 2.5/2.6 version available. I click "New features with Apache 2.5/2.6" link in the page, but get "page not found" error. So, what is the problem?
Apache httpd uses the classic three numbers versioning scheme
Major.Minor.Patchlevel
and uses the Minor version number to distinguish between development versions (odd Minor number) and stable, released versions (even Minor number).
So 2.4.52 is the most recent released version as of the time of this writing.
The 2.5.x versions also exist, being in-progress unstable and unreleased development versions targetted at developers only. Once the 2.5 series matures and is considered to be ready for a release, it will become the 2.6 stable series, successor of the 2.4 stable series. (Just as the 2.4 series is the successor of the 2.2 series, with all 2.3.x versions being unstable development versions leading up to 2.4.0.)
There is not version 2.6.x yet, as development hasn't finished so far.
Unfortunately, I could not find any official informatin on the Apache httpd website detailing this.
There are multiple versions of IBM mobilefirst platform available. What are the different decision points that need to be considered for choosing a particular IBM mobilefirst version for implementation?
There are only two versions that should be considered at this time: 7.1 and 8.0, and the only reason to choose 7.1 is if you've already invested in a version older than 7.1. The reason I say that is because V8.0 is rearchitected in a number of significant ways that make it more suitable for Cloud deployments and Open development models. Therefore, the cost to migrate from an older version to V8 is somewhat greater than to migrate to 7.1, and 7.1 will continue to support all the latest mobile operating systems. V8 on the other hand has many new features that 7.1 will never have (as you'd expect) If you're looking to play with the technology, go download the free DevKit from https://mobilefirstplatform.ibmcloud.com/.
So bottom line: If this is a new deployment/purchase/etc. then I'd always suggest V8 as the preferred choice. However if you already have an investment in older versions, V8 is still the preferred choice, but migration to V8 may take more time than to migrate to 7.1.
Does that answer your question?
Mobilefirst 7 or 7.1 will be most reliable as of now since it has been in the market for some time and most of the pmr's would already be resolved. Within 7 and 7.1 itself there are few changes like 7 has desktop browser environment which is not present in 7.1. So you would want to check out the differences before chosing 7 or 7.1. But personally I would recommend you to go for mfp8 since there are lots of new features added into it. It might be a bit unstable but eventually everyone would upgrade to 8 is what I feel.
I'm starting to use redis for my applications as a cache backend and "shared memory" store.
I've asked the servers maintenance team to install Redis on our CentOS 6.5 production environments. From EPEL, the version is 2.4.10, which we hope will upgrade in the future. Also, on our internal registry, we have a 3.0.7 available. The maintenance team would prefer the EPEL version.
I'm not quite sure of the differences between the versions. I haven't found a document listing major changes from 2.x to 3.0. Are there major features/ performance improvements/bugfixes in 3.0 that I MUST have?
My first guess is that 2.4.10 would be sufficient enough for my needs.
The most significant change from 2.x to 3.0 is that Redis 3.0 introduces Redis Cluster which is a distributed implementation of Redis.
You can also get change list (bug fix, new features and so on) of other versions from 00-RELEASENOTES file of each version: github link:
I am looking at Nexus 3.00 OSS Edition.
The recent release of Nexus 3.0 (OSS Edition) seems to have dropped support for rpms.
I don't see any specific note declaring that they are going to be dropping some features from 2.x.
So i am not sure whether the rpm/ yum repositry support is actually removed Or is it being supported differently with the new Nexus 3.0 or this feature has been made exclusive for the Paid version.
Not yet. The progress of this can be tracked in http://issues.sonatype.org/browse/NEXUS-10191. Feel free to watch for release details.
Ubuntu shipped CMake 2.8 when version 3.3 was the current version. Other Linux distributions do it similar. Is there a reason like backwards-compatibility issues with CMake 3.0?
I found plenty of people willing to explain how to upgrade CMake to the latest version, but couldn't figure out why it wasn't done by default. I'd like to understand the mentality of keeping it back before I decide to override the decision and upgrade it myself.
Depends on the Linux distribution you're using. A distribution's maintainers cannot ship future versions and often they don't upgrade version with updates as it might break existing applications.
CMake 3.0 has some minor incompatibilities. More important, it got new features and some bugs were fixed. If software relys on these, you'll need a new version.
Btw: With CMake 2.8 the third part of the version number is relevant. They stayed a long time with 2.8.x and added features with increasing x. Then they could not update to 2.9 or 2.10, thus they decided to change the version scheme and increase y in 3.y.
Your question applies to a wider range of software. It is a general question, whether a distribution should stick to defined versions of software they provide or whether they should update it and potentially break the costumers' setup. Enterprise distributions like RHEL or SLE are very conservative and fix bugs for at least a decade. Ubuntu updates it distribution every six month but you can stick to the LTS for three years. Fedora even updates some key components like the kernel after the release. Arch Linux and openSuse Tumbleweed are rolling releases, the update their software almost on a daily bases, when the upstream updates publish new versions.