Server Maintenance

Minimize Downtime During Maintenance

System maintenance, whether planned or in response to failure, is a necessary part of managing infrastructure. Everyone hopes for the former, rather than the latter. We do our system maintenance quarterly here at LINBIT in hopes that the latter is avoided. These maintenance windows are where we install hardware and software updates, test failovers, and give everything a once over to ensure configurations still make sense.

Normally in the case of planned maintenance, users are left waiting for access while IT does whatever they need to do. This leads to a bad user experience. In fact, that is precisely what lead to this blog post. I was looking for a BIOS update for a motherboard in the server room and was presented with this lovely message:

We are sorry!

I just had a bad user experience. And to further the experience, I have no indication as to when it will be back up or available. I guess I’m supposed to keep checking back until I get what I was looking for… if I remember to.

Here at LINBIT we use DRBD for all of our systems. This ensures that they are always on and always available for the end users and our customers. If for some reason you landed on this site and aren’t familiar with DRBD, DRBD is an open source project developed by us, LINBIT. In its simplest form you can think of it as network raid 1, however instead of having  independent disks, you have two (or more if you’re using DRBD9) independent systems. You essentially now need to lose twice the hardware to experience downtime of services.

One commonly ignored or unrealized benefit of using DRBD is that system maintenance and upgrades can be done with minimal to no interruption of services. The length of the interruption is generally tied to the type of deployment – for example if you’re using virtual machines, live migration can be achieved using DRBD resulting in no downtime. If you’re running services on hardware and they need to be stopped and restarted, your downtime will be limited to the failover time.

So how do we do this? Let say you have two servers; Frodo and Sam – Frodo is Primary (running services) and Sam is Secondary. In this example we need to update the BIOS and upgrade the RAM of our servers. Follow these steps

  1. First put the cluster into maintenance mode
  2. Next power off Sam (the secondary server)
    1. We can now install any upgrades or hardware we need to
    2. Power the system up, enter the BIOS and make sure everything is OK
    3. Reboot and update the BIOS
  3. Boot Sam into the OS
    1. At this point you can install any OS updates and reboot again if needed
  4. Once Sam is back up and everything is verified to be in good condition, bring the cluster out of maintenance mode
  5. Now migrate services to Sam – again depending on how things are configured this may or may not cause a few seconds of  unavailability of services
  6. Repeat steps 1-4 for Frodo

There you have it, one of the better kept secret benefits of using DRBD.

CSI Plugin for LINSTOR Complete

This CSI plug-in allows for the use of LINSTOR volumes on Container Orchestrators that implement CSI, such as Kubernetes.

Preliminary work on the CSI plugin for LINSTOR is now complete and is capable of operating as an independent driver. CSI is a project by the Cloud Native Computing Foundation which aims to serve as an industry standard interface for container orchestration platforms. This allows storage vendors to write one storage driver and have it work across multiple platforms with little or no modification.

In practical terms, this means that LINSTOR is primed to work with current and emerging cloud technologies that implement CSI. Currently, work is being done to provide example deployments for Kubernetes, which should allow an easy way for Kubernetes admins to deploy the LINSTOR CSI plug-in.  We expect full support for Kubernetes integration in early 2019.

Get the code on GitHub.

LINBIT SDS Adds Disaster Recovery and Support for Kubernetes

LINBIT SDS (Linux SDS) will showcase cloud-native enterprise storage management at KubeCon + CloudNativeCon in Seattle

Beaverton, OR, Dec. 3, 2018 – LINBIT enhances open source software-defined storage (SDS) by providing disaster recovery (DR) replication for critical data. LINBIT SDS is an enterprise-class storage management solution designed for cloud and container storage workloads.

To simplify administration, enhance user experience, and accelerate integration with other software, LINBIT SDS relies on the pre-existing storage management capabilities native to Linux, such as LVM and DRBD. These capabilities are complemented by LINSTOR, a feature-rich volume management software. One supported storage tool is DRBD, the in-kernel block level data-replication for Linux. By announcing support for DRBD Proxy, LINBIT extends replication to disaster recovery scenarios since DRBD Proxy enables fast and reliable data replication over any distance by resolving network communications and handling data access latencies.

“LINBIT SDS is rapidly becoming the reliable, high performance, and economical choice for enterprise and cloud workloads,” said Brian Hellman COO of LINBIT. “With simplified support for DR, LINBIT SDS is surpassing the costly and complex proprietary cloud storage solutions.”

LINBIT SDS provides a host of capabilities to manage persistent block storage for Kubernetes environments. It supports logical volume management (LVM) snapshots, which enhance application availability while minimizing data loss; thin provisioning, which improves efficient resource utilization in virtualized environments; and volume management, which simplifies tasks such as adding, removing, or replicating storage volumes.

LINBIT SDS supports Kubernetes

The Linux based SDS solution works with the leading cloud projects Kubernetes, OpenStack, and OpenNebula, as well as a range of virtualization platforms, and as a stand-alone product. Learn more about how the software works by watching a short video-demo here:

Persistent Kubernetes Storage for Databases (MySQL) with LINSTOR and DRBD (Demo)

OpenStack Cinder: Open-Source Volume Management with LINSTOR and DRBD

Linux Disaster Recovery Replication with DRBD Proxy (Demo)

Kubernetes + LINSTOR Container Failover (Demo)

LINBIT is a member of the Linux Foundation and is proud to support KubeCon, a Linux Foundation conference. Visit us at KubeCon + CloudNativeCon at booth #S7, December 11th-13th, 2018 in Seattle.

ABOUT LINBIT

LINBIT is the force behind DRBD and is the de facto open standard for High Availability (HA) software for enterprise and cloud computing. The LINBIT DRBD software is deployed in millions of mission-critical environments worldwide to provide High Availability (HA), Geo-Clustering for Disaster Recovery (DR), and Software Defined Storage (SDS) for OpenStack and OpenNebula based clouds. Don’t be shy. Visit us at LINBIT.com.

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