LVM and the Ease of Migrating to a New Drive

Online data relocation to other drives using LVM and pvmove

These days my disks are filling up fast. My current PC holds 7 drives, including 2 NVMe drives. Actually 8 drives as I installed a new HDD today. All of my disks and partitions – with the notable exception of the FAT16 EFI partition for UEFI boot – are using LVM, the Logical Volume Manager.

With the availability of larger drives at reasonable costs, I decided to move some logical volumes (LV) spanning several drives onto one single drive, thus consolidating disks. This one drive will then be mirrored in a RAID-1 configuration for redundancy.

Note: In a multi-drive LVM Logical Volume each drive represents a potential point of failure. Moving the data from multiple drives onto one drive reduces that risk.

Continue reading “LVM and the Ease of Migrating to a New Drive”

SSD and S.M.A.R.T.

Two years ago I wrote a post on S.M.A.R.T., an acronym for “Self-Monitoring, Analysis, and Reporting Technology”. In plain English, I’m talking about technology inside a hard drive or SSD that monitors and reports about the health of the drive. While S.M.A.R.T. can give us clues as to the state of the drive, it’s not always an exact science. Some indicators warrant an immediate drive replacement, others can indicate a higher probability of imminent failure. Continue reading “SSD and S.M.A.R.T.”

Tuning VM Disk Performance

Qemu/kvm provides you with a plethora of ways to configure your storage devices. Yet no other type of device shows such a variance in its performance, with disk I/O throughput anywhere from stellar to abysmal using the very same hardware.

In this post I like to show some configuration options that have worked well for me. For an in-depth presentation on the latest developments and features, with hands-on examples, see Storage Performance Tuning for FAST! Virtual Machines. Continue reading “Tuning VM Disk Performance”

Monitoring Hard Drives Using Smartmontools

Yesterday I wrote about Linux security and the need for monitoring hard drives for failure symptoms. As if this was an omen, today the following message popped up on my screen:

smartmontools
Smartmontools notify: Hard Disk Health Warning

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qemu-system-x86_64 -drive options

In an attempt to make the qemu -drive command line options more accessible, here is an extract from the qemu-system-x86_64 man page. You can get the complete man page by entering the following in a terminal window:
man qemu-system-x86_64

The options below are valid for qemu-system-x86_64 version 2.5.0. Please refer to the qemu documentation at qemu.weilnetz.de – look for the version you got and select the corresponding sub-folder. You find the latest documentation (qemu 3.1.50) here. Continue reading “qemu-system-x86_64 -drive options”