Linux

When production database or application servers running RHEL, Rocky Linux, CentOS (7 ~ 9), or Ubuntu (20.04 ~ 24.04 LTS) reach 90%+ disk utilization, scheduling emergency maintenance downtime is rarely an acceptable option. In modern virtualization (VMware, KVM, Nutanix, SimpliVity) and cloud infrastructures, performing 100% online, non-disruptive storage expansion is an essential skill for system engineers. Here is the battle-tested standard operating procedure for triggering a kernel SCSI bus rescan, extending LVM physical/logical volumes, and expanding filesystems (XFS vs EXT4) without unmounting. ...

When delivering an HPE SimpliVity with VME (VM Essentials) 2-node cluster to an enterprise customer, you will almost invariably hear the client’s IT team request: “Please just host the Arbiter VM directly on the newly delivered SimpliVity nodes.” To an experienced systems engineer, this request highlights two critical architectural and commercial dilemmas. 1. The Field Dilemmas: Chicken-and-Egg & The Licensing Trap Dilemma 1: The Arbiter Must Exist Before SimpliVity Storage is Created A 2-node SimpliVity cluster requires active network communication with an Arbiter IP before the cluster creation wizard can even begin. If the SimpliVity nodes haven’t been initialized and no storage pool exists, where can you run the Arbiter VM? It is a classic chicken-and-egg paradox. ...